content/browser/accessibility/browser_accessibility_android.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/accessibility/browser_accessibility_android.h"
   6
   7 #include "base/i18n/break_iterator.h"
   8 #include "base/strings/string_util.h"
   9 #include "base/strings/stringprintf.h"
  10 #include "base/strings/utf_string_conversions.h"
  11 #include "content/browser/accessibility/browser_accessibility_manager_android.h"
  12 #include "content/common/accessibility_messages.h"
  13
  14 namespace {
  15
  16 // These are enums from android.text.InputType in Java:
  17 enum {
  18   ANDROID_TEXT_INPUTTYPE_TYPE_NULL = 0,
  19   ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME = 0x4,
  20   ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME_DATE = 0x14,
  21   ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME_TIME = 0x24,
  22   ANDROID_TEXT_INPUTTYPE_TYPE_NUMBER = 0x2,
  23   ANDROID_TEXT_INPUTTYPE_TYPE_PHONE = 0x3,
  24   ANDROID_TEXT_INPUTTYPE_TYPE_TEXT = 0x1,
  25   ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_URI = 0x11,
  26   ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_WEB_EDIT_TEXT = 0xa1,
  27   ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_WEB_EMAIL = 0xd1,
  28   ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_WEB_PASSWORD = 0xe1
  29 };
  30
  31 // These are enums from android.view.View in Java:
  32 enum {
  33   ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_NONE = 0,
  34   ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_POLITE = 1,
  35   ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_ASSERTIVE = 2
  36 };
  37
  38 // These are enums from
  39 // android.view.accessibility.AccessibilityNodeInfo.RangeInfo in Java:
  40 enum {
  41   ANDROID_VIEW_ACCESSIBILITY_RANGE_TYPE_FLOAT = 1
  42 };
  43
  44 }  // namespace
  45
  46 namespace content {
  47
  48 // static
  49 BrowserAccessibility* BrowserAccessibility::Create() {
  50   return new BrowserAccessibilityAndroid();
  51 }
  52
  53 BrowserAccessibilityAndroid::BrowserAccessibilityAndroid() {
  54   first_time_ = true;
  55 }
  56
  57 bool BrowserAccessibilityAndroid::IsNative() const {
  58   return true;
  59 }
  60
  61 void BrowserAccessibilityAndroid::OnLocationChanged() {
  62   manager()->NotifyAccessibilityEvent(ui::AX_EVENT_LOCATION_CHANGED, this);
  63 }
  64
  65 bool BrowserAccessibilityAndroid::PlatformIsLeaf() const {
  66   if (InternalChildCount() == 0)
  67     return true;
  68
  69   // Iframes are always allowed to contain children.
  70   if (IsIframe() ||
  71       GetRole() == ui::AX_ROLE_ROOT_WEB_AREA ||
  72       GetRole() == ui::AX_ROLE_WEB_AREA) {
  73     return false;
  74   }
  75
  76   // If it has a focusable child, we definitely can't leave out children.
  77   if (HasFocusableChild())
  78     return false;
  79
  80   // Date and time controls should drop their children.
  81   if (GetRole() == ui::AX_ROLE_DATE || GetRole() == ui::AX_ROLE_INPUT_TIME)
  82     return true;
  83
  84   BrowserAccessibilityManagerAndroid* manager_android =
  85       static_cast<BrowserAccessibilityManagerAndroid*>(manager());
  86   if (manager_android->prune_tree_for_screen_reader()) {
  87     // Headings with text can drop their children.
  88     base::string16 name = GetText();
  89     if (GetRole() == ui::AX_ROLE_HEADING && !name.empty())
  90       return true;
  91
  92     // Focusable nodes with text can drop their children.
  93     if (HasState(ui::AX_STATE_FOCUSABLE) && !name.empty())
  94       return true;
  95
  96     // Nodes with only static text as children can drop their children.
  97     if (HasOnlyStaticTextChildren())
  98       return true;
  99   }
 100
 101   return BrowserAccessibility::PlatformIsLeaf();
 102 }
 103
 104 bool BrowserAccessibilityAndroid::IsCheckable() const {
 105   bool checkable = false;
 106   bool is_aria_pressed_defined;
 107   bool is_mixed;
 108   GetAriaTristate("aria-pressed", &is_aria_pressed_defined, &is_mixed);
 109   if (GetRole() == ui::AX_ROLE_CHECK_BOX ||
 110       GetRole() == ui::AX_ROLE_RADIO_BUTTON ||
 111       GetRole() == ui::AX_ROLE_MENU_ITEM_CHECK_BOX ||
 112       GetRole() == ui::AX_ROLE_MENU_ITEM_RADIO ||
 113       is_aria_pressed_defined) {
 114     checkable = true;
 115   }
 116   if (HasState(ui::AX_STATE_CHECKED))
 117     checkable = true;
 118   return checkable;
 119 }
 120
 121 bool BrowserAccessibilityAndroid::IsChecked() const {
 122   return (HasState(ui::AX_STATE_CHECKED) || HasState(ui::AX_STATE_PRESSED));
 123 }
 124
 125 bool BrowserAccessibilityAndroid::IsClickable() const {
 126   if (!PlatformIsLeaf())
 127     return false;
 128
 129   return IsFocusable() || !GetText().empty();
 130 }
 131
 132 bool BrowserAccessibilityAndroid::IsCollection() const {
 133   return (GetRole() == ui::AX_ROLE_GRID ||
 134           GetRole() == ui::AX_ROLE_LIST ||
 135           GetRole() == ui::AX_ROLE_LIST_BOX ||
 136           GetRole() == ui::AX_ROLE_DESCRIPTION_LIST ||
 137           GetRole() == ui::AX_ROLE_TABLE ||
 138           GetRole() == ui::AX_ROLE_TREE);
 139 }
 140
 141 bool BrowserAccessibilityAndroid::IsCollectionItem() const {
 142   return (GetRole() == ui::AX_ROLE_CELL ||
 143           GetRole() == ui::AX_ROLE_COLUMN_HEADER ||
 144           GetRole() == ui::AX_ROLE_DESCRIPTION_LIST_TERM ||
 145           GetRole() == ui::AX_ROLE_LIST_BOX_OPTION ||
 146           GetRole() == ui::AX_ROLE_LIST_ITEM ||
 147           GetRole() == ui::AX_ROLE_ROW_HEADER ||
 148           GetRole() == ui::AX_ROLE_TREE_ITEM);
 149 }
 150
 151 bool BrowserAccessibilityAndroid::IsContentInvalid() const {
 152   std::string invalid;
 153   return GetHtmlAttribute("aria-invalid", &invalid);
 154 }
 155
 156 bool BrowserAccessibilityAndroid::IsDismissable() const {
 157   return false;  // No concept of "dismissable" on the web currently.
 158 }
 159
 160 bool BrowserAccessibilityAndroid::IsEditableText() const {
 161   return GetRole() == ui::AX_ROLE_TEXT_FIELD;
 162 }
 163
 164 bool BrowserAccessibilityAndroid::IsEnabled() const {
 165   return HasState(ui::AX_STATE_ENABLED);
 166 }
 167
 168 bool BrowserAccessibilityAndroid::IsFocusable() const {
 169   bool focusable = HasState(ui::AX_STATE_FOCUSABLE);
 170   if (IsIframe() ||
 171       GetRole() == ui::AX_ROLE_WEB_AREA) {
 172     focusable = false;
 173   }
 174   return focusable;
 175 }
 176
 177 bool BrowserAccessibilityAndroid::IsFocused() const {
 178   return manager()->GetFocus(manager()->GetRoot()) == this;
 179 }
 180
 181 bool BrowserAccessibilityAndroid::IsHeading() const {
 182   BrowserAccessibilityAndroid* parent =
 183       static_cast<BrowserAccessibilityAndroid*>(GetParent());
 184   if (parent && parent->IsHeading())
 185     return true;
 186
 187   return (GetRole() == ui::AX_ROLE_COLUMN_HEADER ||
 188           GetRole() == ui::AX_ROLE_HEADING ||
 189           GetRole() == ui::AX_ROLE_ROW_HEADER);
 190 }
 191
 192 bool BrowserAccessibilityAndroid::IsHierarchical() const {
 193   return (GetRole() == ui::AX_ROLE_LIST ||
 194           GetRole() == ui::AX_ROLE_DESCRIPTION_LIST ||
 195           GetRole() == ui::AX_ROLE_TREE);
 196 }
 197
 198 bool BrowserAccessibilityAndroid::IsLink() const {
 199   return (GetRole() == ui::AX_ROLE_LINK ||
 200          GetRole() == ui::AX_ROLE_IMAGE_MAP_LINK);
 201 }
 202
 203 bool BrowserAccessibilityAndroid::IsMultiLine() const {
 204   return HasState(ui::AX_STATE_MULTILINE);
 205 }
 206
 207 bool BrowserAccessibilityAndroid::IsPassword() const {
 208   return HasState(ui::AX_STATE_PROTECTED);
 209 }
 210
 211 bool BrowserAccessibilityAndroid::IsRangeType() const {
 212   return (GetRole() == ui::AX_ROLE_PROGRESS_INDICATOR ||
 213           GetRole() == ui::AX_ROLE_METER ||
 214           GetRole() == ui::AX_ROLE_SCROLL_BAR ||
 215           GetRole() == ui::AX_ROLE_SLIDER);
 216 }
 217
 218 bool BrowserAccessibilityAndroid::IsScrollable() const {
 219   return (HasIntAttribute(ui::AX_ATTR_SCROLL_X_MAX) &&
 220           GetRole() != ui::AX_ROLE_SCROLL_AREA);
 221 }
 222
 223 bool BrowserAccessibilityAndroid::IsSelected() const {
 224   return HasState(ui::AX_STATE_SELECTED);
 225 }
 226
 227 bool BrowserAccessibilityAndroid::IsSlider() const {
 228   return GetRole() == ui::AX_ROLE_SLIDER;
 229 }
 230
 231 bool BrowserAccessibilityAndroid::IsVisibleToUser() const {
 232   return !HasState(ui::AX_STATE_INVISIBLE);
 233 }
 234
 235 bool BrowserAccessibilityAndroid::CanOpenPopup() const {
 236   return HasState(ui::AX_STATE_HASPOPUP);
 237 }
 238
 239 const char* BrowserAccessibilityAndroid::GetClassName() const {
 240   const char* class_name = NULL;
 241
 242   switch (GetRole()) {
 243     case ui::AX_ROLE_SEARCH_BOX:
 244     case ui::AX_ROLE_SPIN_BUTTON:
 245     case ui::AX_ROLE_TEXT_FIELD:
 246       class_name = "android.widget.EditText";
 247       break;
 248     case ui::AX_ROLE_SLIDER:
 249       class_name = "android.widget.SeekBar";
 250       break;
 251     case ui::AX_ROLE_COLOR_WELL:
 252     case ui::AX_ROLE_COMBO_BOX:
 253     case ui::AX_ROLE_DATE:
 254     case ui::AX_ROLE_POP_UP_BUTTON:
 255     case ui::AX_ROLE_INPUT_TIME:
 256       class_name = "android.widget.Spinner";
 257       break;
 258     case ui::AX_ROLE_BUTTON:
 259     case ui::AX_ROLE_MENU_BUTTON:
 260       class_name = "android.widget.Button";
 261       break;
 262     case ui::AX_ROLE_CHECK_BOX:
 263     case ui::AX_ROLE_SWITCH:
 264       class_name = "android.widget.CheckBox";
 265       break;
 266     case ui::AX_ROLE_RADIO_BUTTON:
 267       class_name = "android.widget.RadioButton";
 268       break;
 269     case ui::AX_ROLE_TOGGLE_BUTTON:
 270       class_name = "android.widget.ToggleButton";
 271       break;
 272     case ui::AX_ROLE_CANVAS:
 273     case ui::AX_ROLE_IMAGE:
 274     case ui::AX_ROLE_SVG_ROOT:
 275       class_name = "android.widget.Image";
 276       break;
 277     case ui::AX_ROLE_METER:
 278     case ui::AX_ROLE_PROGRESS_INDICATOR:
 279       class_name = "android.widget.ProgressBar";
 280       break;
 281     case ui::AX_ROLE_TAB_LIST:
 282       class_name = "android.widget.TabWidget";
 283       break;
 284     case ui::AX_ROLE_GRID:
 285     case ui::AX_ROLE_TABLE:
 286       class_name = "android.widget.GridView";
 287       break;
 288     case ui::AX_ROLE_LIST:
 289     case ui::AX_ROLE_LIST_BOX:
 290     case ui::AX_ROLE_DESCRIPTION_LIST:
 291       class_name = "android.widget.ListView";
 292       break;
 293     case ui::AX_ROLE_DIALOG:
 294       class_name = "android.app.Dialog";
 295       break;
 296     case ui::AX_ROLE_ROOT_WEB_AREA:
 297       class_name = "android.webkit.WebView";
 298       break;
 299     case ui::AX_ROLE_MENU_ITEM:
 300     case ui::AX_ROLE_MENU_ITEM_CHECK_BOX:
 301     case ui::AX_ROLE_MENU_ITEM_RADIO:
 302       class_name = "android.view.MenuItem";
 303       break;
 304     default:
 305       class_name = "android.view.View";
 306       break;
 307   }
 308
 309   return class_name;
 310 }
 311
 312 base::string16 BrowserAccessibilityAndroid::GetText() const {
 313   if (IsIframe() ||
 314       GetRole() == ui::AX_ROLE_WEB_AREA) {
 315     return base::string16();
 316   }
 317
 318   // See comment in browser_accessibility_win.cc for details.
 319   // The difference here is that we can only expose one accessible
 320   // name on Android, not 2 or 3 like on Windows or Mac.
 321
 322   // First, always return the |value| attribute if this is an
 323   // input field.
 324   base::string16 value = GetString16Attribute(ui::AX_ATTR_VALUE);
 325   if (!value.empty()) {
 326     if (HasState(ui::AX_STATE_EDITABLE))
 327       return value;
 328
 329     switch (GetRole()) {
 330       case ui::AX_ROLE_COMBO_BOX:
 331       case ui::AX_ROLE_POP_UP_BUTTON:
 332       case ui::AX_ROLE_TEXT_FIELD:
 333         return value;
 334     }
 335   }
 336
 337   // For color wells, the color is stored in separate attributes.
 338   // Perhaps we could return color names in the future?
 339   if (GetRole() == ui::AX_ROLE_COLOR_WELL) {
 340     int color = GetIntAttribute(ui::AX_ATTR_COLOR_VALUE);
 341     int red = (color >> 16) & 0xFF;
 342     int green = (color >> 8) & 0xFF;
 343     int blue = color & 0xFF;
 344     return base::UTF8ToUTF16(
 345         base::StringPrintf("#%02X%02X%02X", red, green, blue));
 346   }
 347
 348   // Always prefer visible text if this is a link. Sites sometimes add
 349   // a "title" attribute to a link with more information, but we can't
 350   // lose the link text.
 351   base::string16 name = GetString16Attribute(ui::AX_ATTR_NAME);
 352   if (!name.empty() && GetRole() == ui::AX_ROLE_LINK)
 353     return name;
 354
 355   // If there's no text value, the basic rule is: prefer description
 356   // (aria-labelledby or aria-label), then help (title), then name
 357   // (inner text), then value (control value).  However, if
 358   // title_elem_id is set, that means there's a label element
 359   // supplying the name and then name takes precedence over help.
 360   // TODO(dmazzoni): clean this up by providing more granular labels in
 361   // Blink, making the platform-specific mapping to accessible text simpler.
 362   base::string16 description = GetString16Attribute(ui::AX_ATTR_DESCRIPTION);
 363   base::string16 help = GetString16Attribute(ui::AX_ATTR_HELP);
 364
 365   base::string16 placeholder;
 366   switch (GetRole()) {
 367     case ui::AX_ROLE_DATE:
 368     case ui::AX_ROLE_INPUT_TIME:
 369     case ui::AX_ROLE_TEXT_FIELD:
 370       GetHtmlAttribute("placeholder", &placeholder);
 371   }
 372
 373   int title_elem_id = GetIntAttribute(
 374       ui::AX_ATTR_TITLE_UI_ELEMENT);
 375   base::string16 text;
 376   if (!description.empty())
 377     text = description;
 378   else if (title_elem_id && !name.empty())
 379     text = name;
 380   else if (!help.empty())
 381     text = help;
 382   else if (!name.empty())
 383     text = name;
 384   else if (!placeholder.empty())
 385     text = placeholder;
 386   else if (!value.empty())
 387     text = value;
 388   else if (title_elem_id) {
 389     BrowserAccessibility* title_elem =
 390           manager()->GetFromID(title_elem_id);
 391     if (title_elem)
 392       text = static_cast<BrowserAccessibilityAndroid*>(title_elem)->GetText();
 393   }
 394
 395   // This is called from PlatformIsLeaf, so don't call PlatformChildCount
 396   // from within this!
 397   if (text.empty() &&
 398       (HasOnlyStaticTextChildren() ||
 399        (IsFocusable() && HasOnlyTextAndImageChildren()))) {
 400     for (uint32 i = 0; i < InternalChildCount(); i++) {
 401       BrowserAccessibility* child = InternalGetChild(i);
 402       text += static_cast<BrowserAccessibilityAndroid*>(child)->GetText();
 403     }
 404   }
 405
 406   if (text.empty() && (IsLink() || GetRole() == ui::AX_ROLE_IMAGE)) {
 407     base::string16 url = GetString16Attribute(ui::AX_ATTR_URL);
 408     // Given a url like http://foo.com/bar/baz.png, just return the
 409     // base name, e.g., "baz".
 410     int trailing_slashes = 0;
 411     while (url.size() - trailing_slashes > 0 &&
 412            url[url.size() - trailing_slashes - 1] == '/') {
 413       trailing_slashes++;
 414     }
 415     if (trailing_slashes)
 416       url = url.substr(0, url.size() - trailing_slashes);
 417     size_t slash_index = url.rfind('/');
 418     if (slash_index != std::string::npos)
 419       url = url.substr(slash_index + 1);
 420     size_t dot_index = url.rfind('.');
 421     if (dot_index != std::string::npos)
 422       url = url.substr(0, dot_index);
 423     text = url;
 424   }
 425
 426   return text;
 427 }
 428
 429 int BrowserAccessibilityAndroid::GetItemIndex() const {
 430   int index = 0;
 431   switch (GetRole()) {
 432     case ui::AX_ROLE_LIST_ITEM:
 433     case ui::AX_ROLE_LIST_BOX_OPTION:
 434     case ui::AX_ROLE_TREE_ITEM:
 435       index = GetIntAttribute(ui::AX_ATTR_POS_IN_SET) - 1;
 436       break;
 437     case ui::AX_ROLE_SLIDER:
 438     case ui::AX_ROLE_PROGRESS_INDICATOR: {
 439       // Return a percentage here for live feedback in an AccessibilityEvent.
 440       // The exact value is returned in RangeCurrentValue.
 441       float min = GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
 442       float max = GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
 443       float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
 444       if (max > min && value >= min && value <= max)
 445         index = static_cast<int>(((value - min)) * 100 / (max - min));
 446       break;
 447     }
 448   }
 449   return index;
 450 }
 451
 452 int BrowserAccessibilityAndroid::GetItemCount() const {
 453   int count = 0;
 454   switch (GetRole()) {
 455     case ui::AX_ROLE_LIST:
 456     case ui::AX_ROLE_LIST_BOX:
 457     case ui::AX_ROLE_DESCRIPTION_LIST:
 458       count = PlatformChildCount();
 459       break;
 460     case ui::AX_ROLE_SLIDER:
 461     case ui::AX_ROLE_PROGRESS_INDICATOR:
 462       // An AccessibilityEvent can only return integer information about a
 463       // seek control, so we return a percentage. The real range is returned
 464       // in RangeMin and RangeMax.
 465       count = 100;
 466       break;
 467   }
 468   return count;
 469 }
 470
 471 bool BrowserAccessibilityAndroid::CanScrollForward() const {
 472   if (IsSlider()) {
 473     float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
 474     float max = GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
 475     return value < max;
 476   } else {
 477     return GetScrollX() < GetMaxScrollX() ||
 478            GetScrollY() < GetMaxScrollY();
 479   }
 480 }
 481
 482 bool BrowserAccessibilityAndroid::CanScrollBackward() const {
 483   if (IsSlider()) {
 484     float value = GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
 485     float min = GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
 486     return value > min;
 487   } else {
 488     return GetScrollX() > GetMinScrollX() ||
 489            GetScrollY() > GetMinScrollY();
 490   }
 491 }
 492
 493 bool BrowserAccessibilityAndroid::CanScrollUp() const {
 494   return GetScrollY() > GetMinScrollY();
 495 }
 496
 497 bool BrowserAccessibilityAndroid::CanScrollDown() const {
 498   return GetScrollY() < GetMaxScrollY();
 499 }
 500
 501 bool BrowserAccessibilityAndroid::CanScrollLeft() const {
 502   return GetScrollX() > GetMinScrollX();
 503 }
 504
 505 bool BrowserAccessibilityAndroid::CanScrollRight() const {
 506   return GetScrollX() < GetMaxScrollX();
 507 }
 508
 509 int BrowserAccessibilityAndroid::GetScrollX() const {
 510   int value = 0;
 511   GetIntAttribute(ui::AX_ATTR_SCROLL_X, &value);
 512   return value;
 513 }
 514
 515 int BrowserAccessibilityAndroid::GetScrollY() const {
 516   int value = 0;
 517   GetIntAttribute(ui::AX_ATTR_SCROLL_Y, &value);
 518   return value;
 519 }
 520
 521 int BrowserAccessibilityAndroid::GetMinScrollX() const {
 522   return GetIntAttribute(ui::AX_ATTR_SCROLL_X_MIN);
 523 }
 524
 525 int BrowserAccessibilityAndroid::GetMinScrollY() const {
 526   return GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MIN);
 527 }
 528
 529 int BrowserAccessibilityAndroid::GetMaxScrollX() const {
 530   return GetIntAttribute(ui::AX_ATTR_SCROLL_X_MAX);
 531 }
 532
 533 int BrowserAccessibilityAndroid::GetMaxScrollY() const {
 534   return GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MAX);
 535 }
 536
 537 bool BrowserAccessibilityAndroid::Scroll(int direction) const {
 538   int x = GetIntAttribute(ui::AX_ATTR_SCROLL_X);
 539   int x_min = GetIntAttribute(ui::AX_ATTR_SCROLL_X_MIN);
 540   int x_max = GetIntAttribute(ui::AX_ATTR_SCROLL_X_MAX);
 541   int y = GetIntAttribute(ui::AX_ATTR_SCROLL_Y);
 542   int y_min = GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MIN);
 543   int y_max = GetIntAttribute(ui::AX_ATTR_SCROLL_Y_MAX);
 544
 545   // Figure out the bounding box of the visible portion of this scrollable
 546   // view so we know how much to scroll by.
 547   gfx::Rect bounds;
 548   if (GetRole() == ui::AX_ROLE_ROOT_WEB_AREA) {
 549     // If this is the root web area, use the bounds of the view to determine
 550     // how big one page is.
 551     if (!manager()->delegate())
 552       return false;
 553     bounds = manager()->delegate()->AccessibilityGetViewBounds();
 554   } else if (GetRole() == ui::AX_ROLE_WEB_AREA) {
 555     // If this is a web area inside of an iframe, try to use the bounds of
 556     // the containing element.
 557     BrowserAccessibility* parent = GetParent();
 558     while (parent && (parent->GetLocation().width() == 0 ||
 559                       parent->GetLocation().height() == 0)) {
 560       parent = parent->GetParent();
 561     }
 562     if (parent)
 563       bounds = parent->GetLocation();
 564     else
 565       bounds = GetLocation();
 566   } else {
 567     // Otherwise this is something like a scrollable div, just use the
 568     // bounds of this object itself.
 569     bounds = GetLocation();
 570   }
 571
 572   // Scroll by 80% of one page.
 573   int page_x = std::max(bounds.width() * 4 / 5, 1);
 574   int page_y = std::max(bounds.height() * 4 / 5, 1);
 575
 576   if (direction == FORWARD)
 577     direction = y_max > y_min ? DOWN : RIGHT;
 578   if (direction == BACKWARD)
 579     direction = y_max > y_min ? UP : LEFT;
 580
 581   switch (direction) {
 582     case UP:
 583       y = std::min(std::max(y - page_y, y_min), y_max);
 584       break;
 585     case DOWN:
 586       y = std::min(std::max(y + page_y, y_min), y_max);
 587       break;
 588     case LEFT:
 589       x = std::min(std::max(x - page_x, x_min), x_max);
 590       break;
 591     case RIGHT:
 592       x = std::min(std::max(x + page_x, x_min), x_max);
 593       break;
 594     default:
 595       NOTREACHED();
 596   }
 597
 598   manager()->SetScrollOffset(*this, gfx::Point(x, y));
 599   return true;
 600 }
 601
 602 // Given arbitrary old_value_ and new_value_, we must come up with reasonable
 603 // edit metrics. Although edits like "apple" > "apples" are typical, anything
 604 // is possible, such as "apple" > "applesauce", "apple" > "boot", or "" >
 605 // "supercalifragilisticexpialidocious". So we consider old_value_ to be of the
 606 // form AXB and new_value_ to be of the form AYB, where X and Y are the pieces
 607 // that don't match. We take the X to be the "removed" characters and Y to be
 608 // the "added" characters.
 609
 610 int BrowserAccessibilityAndroid::GetTextChangeFromIndex() const {
 611   // This is len(A)
 612   return CommonPrefixLength(old_value_, new_value_);
 613 }
 614
 615 int BrowserAccessibilityAndroid::GetTextChangeAddedCount() const {
 616   // This is len(AYB) - (len(A) + len(B)), or len(Y), the added characters.
 617   return new_value_.length() - CommonEndLengths(old_value_, new_value_);
 618 }
 619
 620 int BrowserAccessibilityAndroid::GetTextChangeRemovedCount() const {
 621   // This is len(AXB) - (len(A) + len(B)), or len(X), the removed characters.
 622   return old_value_.length() - CommonEndLengths(old_value_, new_value_);
 623 }
 624
 625 // static
 626 size_t BrowserAccessibilityAndroid::CommonPrefixLength(
 627     const base::string16 a,
 628     const base::string16 b) {
 629   size_t a_len = a.length();
 630   size_t b_len = b.length();
 631   size_t i = 0;
 632   while (i < a_len &&
 633          i < b_len &&
 634          a[i] == b[i]) {
 635     i++;
 636   }
 637   return i;
 638 }
 639
 640 // static
 641 size_t BrowserAccessibilityAndroid::CommonSuffixLength(
 642     const base::string16 a,
 643     const base::string16 b) {
 644   size_t a_len = a.length();
 645   size_t b_len = b.length();
 646   size_t i = 0;
 647   while (i < a_len &&
 648          i < b_len &&
 649          a[a_len - i - 1] == b[b_len - i - 1]) {
 650     i++;
 651   }
 652   return i;
 653 }
 654
 655 // static
 656 size_t BrowserAccessibilityAndroid::CommonEndLengths(
 657     const base::string16 a,
 658     const base::string16 b) {
 659   size_t prefix_len = CommonPrefixLength(a, b);
 660   // Remove the matching prefix before finding the suffix. Otherwise, if
 661   // old_value_ is "a" and new_value_ is "aa", "a" will be double-counted as
 662   // both a prefix and a suffix of "aa".
 663   base::string16 a_body = a.substr(prefix_len, std::string::npos);
 664   base::string16 b_body = b.substr(prefix_len, std::string::npos);
 665   size_t suffix_len = CommonSuffixLength(a_body, b_body);
 666   return prefix_len + suffix_len;
 667 }
 668
 669 base::string16 BrowserAccessibilityAndroid::GetTextChangeBeforeText() const {
 670   return old_value_;
 671 }
 672
 673 int BrowserAccessibilityAndroid::GetSelectionStart() const {
 674   int sel_start = 0;
 675   GetIntAttribute(ui::AX_ATTR_TEXT_SEL_START, &sel_start);
 676   return sel_start;
 677 }
 678
 679 int BrowserAccessibilityAndroid::GetSelectionEnd() const {
 680   int sel_end = 0;
 681   GetIntAttribute(ui::AX_ATTR_TEXT_SEL_END, &sel_end);
 682   return sel_end;
 683 }
 684
 685 int BrowserAccessibilityAndroid::GetEditableTextLength() const {
 686   base::string16 value = GetString16Attribute(ui::AX_ATTR_VALUE);
 687   return value.length();
 688 }
 689
 690 int BrowserAccessibilityAndroid::AndroidInputType() const {
 691   std::string html_tag = GetStringAttribute(
 692       ui::AX_ATTR_HTML_TAG);
 693   if (html_tag != "input")
 694     return ANDROID_TEXT_INPUTTYPE_TYPE_NULL;
 695
 696   std::string type;
 697   if (!GetHtmlAttribute("type", &type))
 698     return ANDROID_TEXT_INPUTTYPE_TYPE_TEXT;
 699
 700   if (type.empty() || type == "text" || type == "search")
 701     return ANDROID_TEXT_INPUTTYPE_TYPE_TEXT;
 702   else if (type == "date")
 703     return ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME_DATE;
 704   else if (type == "datetime" || type == "datetime-local")
 705     return ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME;
 706   else if (type == "email")
 707     return ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_WEB_EMAIL;
 708   else if (type == "month")
 709     return ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME_DATE;
 710   else if (type == "number")
 711     return ANDROID_TEXT_INPUTTYPE_TYPE_NUMBER;
 712   else if (type == "password")
 713     return ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_WEB_PASSWORD;
 714   else if (type == "tel")
 715     return ANDROID_TEXT_INPUTTYPE_TYPE_PHONE;
 716   else if (type == "time")
 717     return ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME_TIME;
 718   else if (type == "url")
 719     return ANDROID_TEXT_INPUTTYPE_TYPE_TEXT_URI;
 720   else if (type == "week")
 721     return ANDROID_TEXT_INPUTTYPE_TYPE_DATETIME;
 722
 723   return ANDROID_TEXT_INPUTTYPE_TYPE_NULL;
 724 }
 725
 726 int BrowserAccessibilityAndroid::AndroidLiveRegionType() const {
 727   std::string live = GetStringAttribute(
 728       ui::AX_ATTR_LIVE_STATUS);
 729   if (live == "polite")
 730     return ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_POLITE;
 731   else if (live == "assertive")
 732     return ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_ASSERTIVE;
 733   return ANDROID_VIEW_VIEW_ACCESSIBILITY_LIVE_REGION_NONE;
 734 }
 735
 736 int BrowserAccessibilityAndroid::AndroidRangeType() const {
 737   return ANDROID_VIEW_ACCESSIBILITY_RANGE_TYPE_FLOAT;
 738 }
 739
 740 int BrowserAccessibilityAndroid::RowCount() const {
 741   if (GetRole() == ui::AX_ROLE_GRID ||
 742       GetRole() == ui::AX_ROLE_TABLE) {
 743     return CountChildrenWithRole(ui::AX_ROLE_ROW);
 744   }
 745
 746   if (GetRole() == ui::AX_ROLE_LIST ||
 747       GetRole() == ui::AX_ROLE_LIST_BOX ||
 748       GetRole() == ui::AX_ROLE_DESCRIPTION_LIST ||
 749       GetRole() == ui::AX_ROLE_TREE) {
 750     return PlatformChildCount();
 751   }
 752
 753   return 0;
 754 }
 755
 756 int BrowserAccessibilityAndroid::ColumnCount() const {
 757   if (GetRole() == ui::AX_ROLE_GRID ||
 758       GetRole() == ui::AX_ROLE_TABLE) {
 759     return CountChildrenWithRole(ui::AX_ROLE_COLUMN);
 760   }
 761   return 0;
 762 }
 763
 764 int BrowserAccessibilityAndroid::RowIndex() const {
 765   if (GetRole() == ui::AX_ROLE_LIST_ITEM ||
 766       GetRole() == ui::AX_ROLE_LIST_BOX_OPTION ||
 767       GetRole() == ui::AX_ROLE_TREE_ITEM) {
 768     return GetIndexInParent();
 769   }
 770
 771   return GetIntAttribute(ui::AX_ATTR_TABLE_CELL_ROW_INDEX);
 772 }
 773
 774 int BrowserAccessibilityAndroid::RowSpan() const {
 775   return GetIntAttribute(ui::AX_ATTR_TABLE_CELL_ROW_SPAN);
 776 }
 777
 778 int BrowserAccessibilityAndroid::ColumnIndex() const {
 779   return GetIntAttribute(ui::AX_ATTR_TABLE_CELL_COLUMN_INDEX);
 780 }
 781
 782 int BrowserAccessibilityAndroid::ColumnSpan() const {
 783   return GetIntAttribute(ui::AX_ATTR_TABLE_CELL_COLUMN_SPAN);
 784 }
 785
 786 float BrowserAccessibilityAndroid::RangeMin() const {
 787   return GetFloatAttribute(ui::AX_ATTR_MIN_VALUE_FOR_RANGE);
 788 }
 789
 790 float BrowserAccessibilityAndroid::RangeMax() const {
 791   return GetFloatAttribute(ui::AX_ATTR_MAX_VALUE_FOR_RANGE);
 792 }
 793
 794 float BrowserAccessibilityAndroid::RangeCurrentValue() const {
 795   return GetFloatAttribute(ui::AX_ATTR_VALUE_FOR_RANGE);
 796 }
 797
 798 void BrowserAccessibilityAndroid::GetGranularityBoundaries(
 799     int granularity,
 800     std::vector<int32>* starts,
 801     std::vector<int32>* ends,
 802     int offset) {
 803   switch (granularity) {
 804     case ANDROID_ACCESSIBILITY_NODE_INFO_MOVEMENT_GRANULARITY_LINE:
 805       GetLineBoundaries(starts, ends, offset);
 806       break;
 807     case ANDROID_ACCESSIBILITY_NODE_INFO_MOVEMENT_GRANULARITY_WORD:
 808       GetWordBoundaries(starts, ends, offset);
 809       break;
 810     default:
 811       NOTREACHED();
 812   }
 813 }
 814
 815 void BrowserAccessibilityAndroid::GetLineBoundaries(
 816     std::vector<int32>* line_starts,
 817     std::vector<int32>* line_ends,
 818     int offset) {
 819   // If this node has no children, treat it as all one line.
 820   if (GetText().size() > 0 && !InternalChildCount()) {
 821     line_starts->push_back(offset);
 822     line_ends->push_back(offset + GetText().size());
 823   }
 824
 825   // If this is a static text node, get the line boundaries from the
 826   // inline text boxes if possible.
 827   if (GetRole() == ui::AX_ROLE_STATIC_TEXT) {
 828     int last_y = 0;
 829     for (uint32 i = 0; i < InternalChildCount(); i++) {
 830       BrowserAccessibilityAndroid* child =
 831           static_cast<BrowserAccessibilityAndroid*>(InternalGetChild(i));
 832       CHECK_EQ(ui::AX_ROLE_INLINE_TEXT_BOX, child->GetRole());
 833       // TODO(dmazzoni): replace this with a proper API to determine
 834       // if two inline text boxes are on the same line. http://crbug.com/421771
 835       int y = child->GetLocation().y();
 836       if (i == 0) {
 837         line_starts->push_back(offset);
 838       } else if (y != last_y) {
 839         line_ends->push_back(offset);
 840         line_starts->push_back(offset);
 841       }
 842       offset += child->GetText().size();
 843       last_y = y;
 844     }
 845     line_ends->push_back(offset);
 846     return;
 847   }
 848
 849   // Otherwise, call GetLineBoundaries recursively on the children.
 850   for (uint32 i = 0; i < InternalChildCount(); i++) {
 851     BrowserAccessibilityAndroid* child =
 852         static_cast<BrowserAccessibilityAndroid*>(InternalGetChild(i));
 853     child->GetLineBoundaries(line_starts, line_ends, offset);
 854     offset += child->GetText().size();
 855   }
 856 }
 857
 858 void BrowserAccessibilityAndroid::GetWordBoundaries(
 859     std::vector<int32>* word_starts,
 860     std::vector<int32>* word_ends,
 861     int offset) {
 862   if (GetRole() == ui::AX_ROLE_INLINE_TEXT_BOX) {
 863     const std::vector<int32>& starts = GetIntListAttribute(
 864         ui::AX_ATTR_WORD_STARTS);
 865     const std::vector<int32>& ends = GetIntListAttribute(
 866         ui::AX_ATTR_WORD_ENDS);
 867     for (size_t i = 0; i < starts.size(); ++i) {
 868       word_starts->push_back(offset + starts[i]);
 869       word_ends->push_back(offset + ends[i]);
 870     }
 871     return;
 872   }
 873
 874   base::string16 concatenated_text;
 875   for (uint32 i = 0; i < InternalChildCount(); i++) {
 876     BrowserAccessibilityAndroid* child =
 877         static_cast<BrowserAccessibilityAndroid*>(InternalGetChild(i));
 878     base::string16 child_text = child->GetText();
 879     concatenated_text += child->GetText();
 880   }
 881
 882   base::string16 text = GetText();
 883   if (text.empty() || concatenated_text == text) {
 884     // Great - this node is just the concatenation of its children, so
 885     // we can get the word boundaries recursively.
 886     for (uint32 i = 0; i < InternalChildCount(); i++) {
 887       BrowserAccessibilityAndroid* child =
 888           static_cast<BrowserAccessibilityAndroid*>(InternalGetChild(i));
 889       child->GetWordBoundaries(word_starts, word_ends, offset);
 890       offset += child->GetText().size();
 891     }
 892   } else {
 893     // This node has its own accessible text that doesn't match its
 894     // visible text - like alt text for an image or something with an
 895     // aria-label, so split the text into words locally.
 896     base::i18n::BreakIterator iter(text, base::i18n::BreakIterator::BREAK_WORD);
 897     if (!iter.Init())
 898       return;
 899     while (iter.Advance()) {
 900       if (iter.IsWord()) {
 901         word_starts->push_back(iter.prev());
 902         word_ends->push_back(iter.pos());
 903       }
 904     }
 905   }
 906 }
 907
 908 bool BrowserAccessibilityAndroid::HasFocusableChild() const {
 909   // This is called from PlatformIsLeaf, so don't call PlatformChildCount
 910   // from within this!
 911   for (uint32 i = 0; i < InternalChildCount(); i++) {
 912     BrowserAccessibility* child = InternalGetChild(i);
 913     if (child->HasState(ui::AX_STATE_FOCUSABLE))
 914       return true;
 915     if (static_cast<BrowserAccessibilityAndroid*>(child)->HasFocusableChild())
 916       return true;
 917   }
 918   return false;
 919 }
 920
 921 bool BrowserAccessibilityAndroid::HasOnlyStaticTextChildren() const {
 922   // This is called from PlatformIsLeaf, so don't call PlatformChildCount
 923   // from within this!
 924   for (uint32 i = 0; i < InternalChildCount(); i++) {
 925     BrowserAccessibility* child = InternalGetChild(i);
 926     if (child->GetRole() != ui::AX_ROLE_STATIC_TEXT)
 927       return false;
 928   }
 929   return true;
 930 }
 931
 932 bool BrowserAccessibilityAndroid::HasOnlyTextAndImageChildren() const {
 933   // This is called from PlatformIsLeaf, so don't call PlatformChildCount
 934   // from within this!
 935   for (uint32 i = 0; i < InternalChildCount(); i++) {
 936     BrowserAccessibility* child = InternalGetChild(i);
 937     if (child->GetRole() != ui::AX_ROLE_STATIC_TEXT &&
 938         child->GetRole() != ui::AX_ROLE_IMAGE) {
 939       return false;
 940     }
 941   }
 942   return true;
 943 }
 944
 945 bool BrowserAccessibilityAndroid::IsIframe() const {
 946   base::string16 html_tag = GetString16Attribute(
 947       ui::AX_ATTR_HTML_TAG);
 948   return html_tag == base::ASCIIToUTF16("iframe");
 949 }
 950
 951 void BrowserAccessibilityAndroid::OnDataChanged() {
 952   BrowserAccessibility::OnDataChanged();
 953
 954   if (IsEditableText()) {
 955     base::string16 value = GetString16Attribute(ui::AX_ATTR_VALUE);
 956     if (value != new_value_) {
 957       old_value_ = new_value_;
 958       new_value_ = value;
 959     }
 960   }
 961
 962   if (GetRole() == ui::AX_ROLE_ALERT && first_time_)
 963     manager()->NotifyAccessibilityEvent(ui::AX_EVENT_ALERT, this);
 964
 965   base::string16 live;
 966   if (GetString16Attribute(
 967       ui::AX_ATTR_CONTAINER_LIVE_STATUS, &live)) {
 968     NotifyLiveRegionUpdate(live);
 969   }
 970
 971   first_time_ = false;
 972 }
 973
 974 void BrowserAccessibilityAndroid::NotifyLiveRegionUpdate(
 975     base::string16& aria_live) {
 976   if (!base::EqualsASCII(aria_live, aria_strings::kAriaLivePolite) &&
 977       !base::EqualsASCII(aria_live, aria_strings::kAriaLiveAssertive))
 978     return;
 979
 980   base::string16 text = GetText();
 981   if (cached_text_ != text) {
 982     if (!text.empty()) {
 983       manager()->NotifyAccessibilityEvent(ui::AX_EVENT_SHOW,
 984                                          this);
 985     }
 986     cached_text_ = text;
 987   }
 988 }
 989
 990 int BrowserAccessibilityAndroid::CountChildrenWithRole(ui::AXRole role) const {
 991   int count = 0;
 992   for (uint32 i = 0; i < PlatformChildCount(); i++) {
 993     if (PlatformGetChild(i)->GetRole() == role)
 994       count++;
 995   }
 996   return count;
 997 }
 998
 999 }  // namespace content