android_webview/browser/browser_view_renderer.cc

   1 // Copyright 2014 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 "android_webview/browser/browser_view_renderer.h"
   6
   7 #include "android_webview/browser/browser_view_renderer_client.h"
   8 #include "android_webview/browser/child_frame.h"
   9 #include "base/auto_reset.h"
  10 #include "base/command_line.h"
  11 #include "base/logging.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "base/supports_user_data.h"
  15 #include "base/trace_event/trace_event_argument.h"
  16 #include "cc/output/compositor_frame.h"
  17 #include "content/public/browser/web_contents.h"
  18 #include "content/public/common/content_switches.h"
  19 #include "gpu/command_buffer/service/gpu_switches.h"
  20 #include "third_party/skia/include/core/SkBitmap.h"
  21 #include "third_party/skia/include/core/SkCanvas.h"
  22 #include "third_party/skia/include/core/SkPicture.h"
  23 #include "third_party/skia/include/core/SkPictureRecorder.h"
  24 #include "ui/gfx/geometry/vector2d_conversions.h"
  25
  26 namespace android_webview {
  27
  28 namespace {
  29
  30 const double kEpsilon = 1e-8;
  31
  32 const int64 kFallbackTickTimeoutInMilliseconds = 100;
  33
  34 // Used to calculate memory allocation. Determined experimentally.
  35 const size_t kMemoryMultiplier = 20;
  36 const size_t kBytesPerPixel = 4;
  37 const size_t kMemoryAllocationStep = 5 * 1024 * 1024;
  38 uint64 g_memory_override_in_bytes = 0u;
  39
  40 const void* kBrowserViewRendererUserDataKey = &kBrowserViewRendererUserDataKey;
  41
  42 class BrowserViewRendererUserData : public base::SupportsUserData::Data {
  43  public:
  44   BrowserViewRendererUserData(BrowserViewRenderer* ptr) : bvr_(ptr) {}
  45
  46   static BrowserViewRenderer* GetBrowserViewRenderer(
  47       content::WebContents* web_contents) {
  48     if (!web_contents)
  49       return NULL;
  50     BrowserViewRendererUserData* data =
  51         static_cast<BrowserViewRendererUserData*>(
  52             web_contents->GetUserData(kBrowserViewRendererUserDataKey));
  53     return data ? data->bvr_ : NULL;
  54   }
  55
  56  private:
  57   BrowserViewRenderer* bvr_;
  58 };
  59
  60 }  // namespace
  61
  62 // static
  63 void BrowserViewRenderer::CalculateTileMemoryPolicy() {
  64   base::CommandLine* cl = base::CommandLine::ForCurrentProcess();
  65
  66   // If the value was overridden on the command line, use the specified value.
  67   bool client_hard_limit_bytes_overridden =
  68       cl->HasSwitch(switches::kForceGpuMemAvailableMb);
  69   if (client_hard_limit_bytes_overridden) {
  70     base::StringToUint64(
  71         base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
  72             switches::kForceGpuMemAvailableMb),
  73         &g_memory_override_in_bytes);
  74     g_memory_override_in_bytes *= 1024 * 1024;
  75   }
  76 }
  77
  78 // static
  79 BrowserViewRenderer* BrowserViewRenderer::FromWebContents(
  80     content::WebContents* web_contents) {
  81   return BrowserViewRendererUserData::GetBrowserViewRenderer(web_contents);
  82 }
  83
  84 BrowserViewRenderer::BrowserViewRenderer(
  85     BrowserViewRendererClient* client,
  86     const scoped_refptr<base::SingleThreadTaskRunner>& ui_task_runner)
  87     : client_(client),
  88       shared_renderer_state_(ui_task_runner, this),
  89       ui_task_runner_(ui_task_runner),
  90       compositor_(NULL),
  91       is_paused_(false),
  92       view_visible_(false),
  93       window_visible_(false),
  94       attached_to_window_(false),
  95       hardware_enabled_(false),
  96       dip_scale_(0.0),
  97       page_scale_factor_(1.0),
  98       on_new_picture_enable_(false),
  99       clear_view_(false),
 100       offscreen_pre_raster_(false),
 101       fallback_tick_pending_(false) {
 102 }
 103
 104 BrowserViewRenderer::~BrowserViewRenderer() {
 105 }
 106
 107 void BrowserViewRenderer::RegisterWithWebContents(
 108     content::WebContents* web_contents) {
 109   web_contents->SetUserData(kBrowserViewRendererUserDataKey,
 110                             new BrowserViewRendererUserData(this));
 111 }
 112
 113 SharedRendererState* BrowserViewRenderer::GetAwDrawGLViewContext() {
 114   return &shared_renderer_state_;
 115 }
 116
 117 bool BrowserViewRenderer::RequestDrawGL(bool wait_for_completion) {
 118   return client_->RequestDrawGL(wait_for_completion);
 119 }
 120
 121 void BrowserViewRenderer::TrimMemory(const int level, const bool visible) {
 122   DCHECK(ui_task_runner_->BelongsToCurrentThread());
 123   // Constants from Android ComponentCallbacks2.
 124   enum {
 125     TRIM_MEMORY_RUNNING_LOW = 10,
 126     TRIM_MEMORY_UI_HIDDEN = 20,
 127     TRIM_MEMORY_BACKGROUND = 40,
 128     TRIM_MEMORY_MODERATE = 60,
 129   };
 130
 131   // Not urgent enough. TRIM_MEMORY_UI_HIDDEN is treated specially because
 132   // it does not indicate memory pressure, but merely that the app is
 133   // backgrounded.
 134   if (level < TRIM_MEMORY_RUNNING_LOW || level == TRIM_MEMORY_UI_HIDDEN)
 135     return;
 136
 137   // Do not release resources on view we expect to get DrawGL soon.
 138   if (level < TRIM_MEMORY_BACKGROUND && visible)
 139     return;
 140
 141   // Nothing to drop.
 142   if (!compositor_ || !hardware_enabled_)
 143     return;
 144
 145   TRACE_EVENT0("android_webview", "BrowserViewRenderer::TrimMemory");
 146
 147   // If offscreen pre-raster is disabled, drop everything in hardware. Otherwise
 148   // keep the tiles and just delete the HardwareRenderer.
 149   if (level >= TRIM_MEMORY_MODERATE) {
 150     if (offscreen_pre_raster_)
 151       shared_renderer_state_.DeleteHardwareRendererOnUI();
 152     else
 153       shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 154     return;
 155   }
 156
 157   // Just set the memory limit to 0 and drop all tiles. This will be reset to
 158   // normal levels in the next DrawGL call.
 159   if (!offscreen_pre_raster_)
 160     compositor_->SetMemoryPolicy(0u);
 161 }
 162
 163 void BrowserViewRenderer::UpdateMemoryPolicy() {
 164   if (!hardware_enabled_) {
 165     compositor_->SetMemoryPolicy(0u);
 166     return;
 167   }
 168
 169   size_t bytes_limit = 0u;
 170   if (g_memory_override_in_bytes) {
 171     bytes_limit = static_cast<size_t>(g_memory_override_in_bytes);
 172   } else {
 173     gfx::Rect interest_rect = offscreen_pre_raster_
 174                                   ? gfx::Rect(size_)
 175                                   : last_on_draw_global_visible_rect_;
 176     size_t width = interest_rect.width();
 177     size_t height = interest_rect.height();
 178     bytes_limit = kMemoryMultiplier * kBytesPerPixel * width * height;
 179     // Round up to a multiple of kMemoryAllocationStep.
 180     bytes_limit =
 181         (bytes_limit / kMemoryAllocationStep + 1) * kMemoryAllocationStep;
 182   }
 183
 184   compositor_->SetMemoryPolicy(bytes_limit);
 185 }
 186
 187 void BrowserViewRenderer::PrepareToDraw(const gfx::Vector2d& scroll,
 188                                         const gfx::Rect& global_visible_rect) {
 189   last_on_draw_scroll_offset_ = scroll;
 190   last_on_draw_global_visible_rect_ = global_visible_rect;
 191 }
 192
 193 bool BrowserViewRenderer::CanOnDraw() {
 194   if (!compositor_) {
 195     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_NoCompositor",
 196                          TRACE_EVENT_SCOPE_THREAD);
 197     return false;
 198   }
 199   if (clear_view_) {
 200     TRACE_EVENT_INSTANT0("android_webview", "EarlyOut_ClearView",
 201                          TRACE_EVENT_SCOPE_THREAD);
 202     return false;
 203   }
 204
 205   return true;
 206 }
 207
 208 bool BrowserViewRenderer::OnDrawHardware() {
 209   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDrawHardware");
 210
 211   shared_renderer_state_.InitializeHardwareDrawIfNeededOnUI();
 212
 213   if (!CanOnDraw()) {
 214     return false;
 215   }
 216
 217   shared_renderer_state_.SetScrollOffsetOnUI(last_on_draw_scroll_offset_);
 218   hardware_enabled_ = true;
 219
 220   return CompositeHw();
 221 }
 222
 223 bool BrowserViewRenderer::CompositeHw() {
 224   CancelFallbackTick();
 225
 226   ReturnResourceFromParent();
 227   UpdateMemoryPolicy();
 228
 229   ParentCompositorDrawConstraints parent_draw_constraints =
 230       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 231   gfx::Size surface_size(size_);
 232   gfx::Rect viewport(surface_size);
 233   gfx::Rect clip = viewport;
 234   gfx::Transform transform_for_tile_priority =
 235       parent_draw_constraints.transform;
 236
 237   // If the WebView is on a layer, WebView does not know what transform is
 238   // applied onto the layer so global visible rect does not make sense here.
 239   // In this case, just use the surface rect for tiling.
 240   gfx::Rect viewport_rect_for_tile_priority;
 241
 242   // Leave viewport_rect_for_tile_priority empty if offscreen_pre_raster_ is on.
 243   if (!offscreen_pre_raster_) {
 244     if (parent_draw_constraints.is_layer) {
 245       viewport_rect_for_tile_priority = parent_draw_constraints.surface_rect;
 246     } else {
 247       viewport_rect_for_tile_priority = last_on_draw_global_visible_rect_;
 248     }
 249   }
 250
 251   scoped_ptr<cc::CompositorFrame> frame =
 252       compositor_->DemandDrawHw(surface_size,
 253                                 gfx::Transform(),
 254                                 viewport,
 255                                 clip,
 256                                 viewport_rect_for_tile_priority,
 257                                 transform_for_tile_priority);
 258   if (!frame.get()) {
 259     TRACE_EVENT_INSTANT0("android_webview", "NoNewFrame",
 260                          TRACE_EVENT_SCOPE_THREAD);
 261     return false;
 262   }
 263
 264   scoped_ptr<ChildFrame> child_frame = make_scoped_ptr(
 265       new ChildFrame(frame.Pass(), viewport_rect_for_tile_priority,
 266                      transform_for_tile_priority, offscreen_pre_raster_,
 267                      parent_draw_constraints.is_layer));
 268
 269   // Uncommitted frame can happen with consecutive fallback ticks.
 270   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 271   shared_renderer_state_.SetCompositorFrameOnUI(child_frame.Pass());
 272   return true;
 273 }
 274
 275 void BrowserViewRenderer::UpdateParentDrawConstraints() {
 276   PostInvalidateWithFallback();
 277   ParentCompositorDrawConstraints parent_draw_constraints =
 278       shared_renderer_state_.GetParentDrawConstraintsOnUI();
 279   client_->ParentDrawConstraintsUpdated(parent_draw_constraints);
 280 }
 281
 282 void BrowserViewRenderer::ReturnUnusedResource(
 283     scoped_ptr<ChildFrame> child_frame) {
 284   if (!child_frame.get() || !child_frame->frame.get())
 285     return;
 286
 287   cc::CompositorFrameAck frame_ack;
 288   cc::TransferableResource::ReturnResources(
 289       child_frame->frame->delegated_frame_data->resource_list,
 290       &frame_ack.resources);
 291   if (compositor_ && !frame_ack.resources.empty())
 292     compositor_->ReturnResources(frame_ack);
 293 }
 294
 295 void BrowserViewRenderer::ReturnResourceFromParent() {
 296   cc::CompositorFrameAck frame_ack;
 297   shared_renderer_state_.SwapReturnedResourcesOnUI(&frame_ack.resources);
 298   if (compositor_ && !frame_ack.resources.empty()) {
 299     compositor_->ReturnResources(frame_ack);
 300   }
 301 }
 302
 303 void BrowserViewRenderer::DetachFunctorFromView() {
 304   client_->DetachFunctorFromView();
 305 }
 306
 307 bool BrowserViewRenderer::OnDrawSoftware(SkCanvas* canvas) {
 308   return CanOnDraw() && CompositeSW(canvas);
 309 }
 310
 311 skia::RefPtr<SkPicture> BrowserViewRenderer::CapturePicture(int width,
 312                                                             int height) {
 313   TRACE_EVENT0("android_webview", "BrowserViewRenderer::CapturePicture");
 314
 315   // Return empty Picture objects for empty SkPictures.
 316   if (width <= 0 || height <= 0) {
 317     SkPictureRecorder emptyRecorder;
 318     emptyRecorder.beginRecording(0, 0);
 319     return skia::AdoptRef(emptyRecorder.endRecording());
 320   }
 321
 322   // Reset scroll back to the origin, will go back to the old
 323   // value when scroll_reset is out of scope.
 324   base::AutoReset<gfx::Vector2dF> scroll_reset(&scroll_offset_dip_,
 325                                                gfx::Vector2dF());
 326
 327   SkPictureRecorder recorder;
 328   SkCanvas* rec_canvas = recorder.beginRecording(width, height, NULL, 0);
 329   if (compositor_)
 330     CompositeSW(rec_canvas);
 331   return skia::AdoptRef(recorder.endRecording());
 332 }
 333
 334 void BrowserViewRenderer::EnableOnNewPicture(bool enabled) {
 335   on_new_picture_enable_ = enabled;
 336 }
 337
 338 void BrowserViewRenderer::ClearView() {
 339   TRACE_EVENT_INSTANT0("android_webview",
 340                        "BrowserViewRenderer::ClearView",
 341                        TRACE_EVENT_SCOPE_THREAD);
 342   if (clear_view_)
 343     return;
 344
 345   clear_view_ = true;
 346   // Always invalidate ignoring the compositor to actually clear the webview.
 347   PostInvalidateWithFallback();
 348 }
 349
 350 void BrowserViewRenderer::SetOffscreenPreRaster(bool enable) {
 351   if (offscreen_pre_raster_ != enable && compositor_)
 352     UpdateMemoryPolicy();
 353
 354   offscreen_pre_raster_ = enable;
 355 }
 356
 357 void BrowserViewRenderer::SetIsPaused(bool paused) {
 358   TRACE_EVENT_INSTANT1("android_webview",
 359                        "BrowserViewRenderer::SetIsPaused",
 360                        TRACE_EVENT_SCOPE_THREAD,
 361                        "paused",
 362                        paused);
 363   is_paused_ = paused;
 364   UpdateCompositorIsActive();
 365 }
 366
 367 void BrowserViewRenderer::SetViewVisibility(bool view_visible) {
 368   TRACE_EVENT_INSTANT1("android_webview",
 369                        "BrowserViewRenderer::SetViewVisibility",
 370                        TRACE_EVENT_SCOPE_THREAD,
 371                        "view_visible",
 372                        view_visible);
 373   view_visible_ = view_visible;
 374 }
 375
 376 void BrowserViewRenderer::SetWindowVisibility(bool window_visible) {
 377   TRACE_EVENT_INSTANT1("android_webview",
 378                        "BrowserViewRenderer::SetWindowVisibility",
 379                        TRACE_EVENT_SCOPE_THREAD,
 380                        "window_visible",
 381                        window_visible);
 382   window_visible_ = window_visible;
 383   UpdateCompositorIsActive();
 384 }
 385
 386 void BrowserViewRenderer::OnSizeChanged(int width, int height) {
 387   TRACE_EVENT_INSTANT2("android_webview",
 388                        "BrowserViewRenderer::OnSizeChanged",
 389                        TRACE_EVENT_SCOPE_THREAD,
 390                        "width",
 391                        width,
 392                        "height",
 393                        height);
 394   size_.SetSize(width, height);
 395 }
 396
 397 void BrowserViewRenderer::OnAttachedToWindow(int width, int height) {
 398   TRACE_EVENT2("android_webview",
 399                "BrowserViewRenderer::OnAttachedToWindow",
 400                "width",
 401                width,
 402                "height",
 403                height);
 404   attached_to_window_ = true;
 405   size_.SetSize(width, height);
 406   UpdateCompositorIsActive();
 407 }
 408
 409 void BrowserViewRenderer::OnDetachedFromWindow() {
 410   TRACE_EVENT0("android_webview", "BrowserViewRenderer::OnDetachedFromWindow");
 411   shared_renderer_state_.ReleaseHardwareDrawIfNeededOnUI();
 412   attached_to_window_ = false;
 413   DCHECK(!hardware_enabled_);
 414   UpdateCompositorIsActive();
 415 }
 416
 417 void BrowserViewRenderer::ReleaseHardware() {
 418   DCHECK(hardware_enabled_);
 419   ReturnUnusedResource(shared_renderer_state_.PassUncommittedFrameOnUI());
 420   ReturnResourceFromParent();
 421   DCHECK(shared_renderer_state_.ReturnedResourcesEmptyOnUI());
 422
 423   if (compositor_) {
 424     compositor_->SetMemoryPolicy(0u);
 425   }
 426
 427   hardware_enabled_ = false;
 428 }
 429
 430 bool BrowserViewRenderer::IsVisible() const {
 431   // Ignore |window_visible_| if |attached_to_window_| is false.
 432   return view_visible_ && (!attached_to_window_ || window_visible_);
 433 }
 434
 435 gfx::Rect BrowserViewRenderer::GetScreenRect() const {
 436   return gfx::Rect(client_->GetLocationOnScreen(), size_);
 437 }
 438
 439 void BrowserViewRenderer::DidInitializeCompositor(
 440     content::SynchronousCompositor* compositor) {
 441   TRACE_EVENT0("android_webview",
 442                "BrowserViewRenderer::DidInitializeCompositor");
 443   DCHECK(compositor);
 444   DCHECK(!compositor_);
 445   compositor_ = compositor;
 446   UpdateCompositorIsActive();
 447 }
 448
 449 void BrowserViewRenderer::DidDestroyCompositor(
 450     content::SynchronousCompositor* compositor) {
 451   TRACE_EVENT0("android_webview", "BrowserViewRenderer::DidDestroyCompositor");
 452   DCHECK(compositor_);
 453   compositor_ = NULL;
 454 }
 455
 456 void BrowserViewRenderer::SetDipScale(float dip_scale) {
 457   dip_scale_ = dip_scale;
 458   CHECK_GT(dip_scale_, 0.f);
 459 }
 460
 461 gfx::Vector2d BrowserViewRenderer::max_scroll_offset() const {
 462   DCHECK_GT(dip_scale_, 0.f);
 463   return gfx::ToCeiledVector2d(gfx::ScaleVector2d(
 464       max_scroll_offset_dip_, dip_scale_ * page_scale_factor_));
 465 }
 466
 467 void BrowserViewRenderer::ScrollTo(gfx::Vector2d scroll_offset) {
 468   gfx::Vector2d max_offset = max_scroll_offset();
 469   gfx::Vector2dF scroll_offset_dip;
 470   // To preserve the invariant that scrolling to the maximum physical pixel
 471   // value also scrolls to the maximum dip pixel value we transform the physical
 472   // offset into the dip offset by using a proportion (instead of dividing by
 473   // dip_scale * page_scale_factor).
 474   if (max_offset.x()) {
 475     scroll_offset_dip.set_x((scroll_offset.x() * max_scroll_offset_dip_.x()) /
 476                             max_offset.x());
 477   }
 478   if (max_offset.y()) {
 479     scroll_offset_dip.set_y((scroll_offset.y() * max_scroll_offset_dip_.y()) /
 480                             max_offset.y());
 481   }
 482
 483   DCHECK_LE(0.f, scroll_offset_dip.x());
 484   DCHECK_LE(0.f, scroll_offset_dip.y());
 485   DCHECK(scroll_offset_dip.x() < max_scroll_offset_dip_.x() ||
 486          scroll_offset_dip.x() - max_scroll_offset_dip_.x() < kEpsilon)
 487       << scroll_offset_dip.x() << " " << max_scroll_offset_dip_.x();
 488   DCHECK(scroll_offset_dip.y() < max_scroll_offset_dip_.y() ||
 489          scroll_offset_dip.y() - max_scroll_offset_dip_.y() < kEpsilon)
 490       << scroll_offset_dip.y() << " " << max_scroll_offset_dip_.y();
 491
 492   if (scroll_offset_dip_ == scroll_offset_dip)
 493     return;
 494
 495   scroll_offset_dip_ = scroll_offset_dip;
 496
 497   TRACE_EVENT_INSTANT2("android_webview",
 498                "BrowserViewRenderer::ScrollTo",
 499                TRACE_EVENT_SCOPE_THREAD,
 500                "x",
 501                scroll_offset_dip.x(),
 502                "y",
 503                scroll_offset_dip.y());
 504
 505   if (compositor_)
 506     compositor_->DidChangeRootLayerScrollOffset();
 507 }
 508
 509 void BrowserViewRenderer::DidUpdateContent() {
 510   TRACE_EVENT_INSTANT0("android_webview",
 511                        "BrowserViewRenderer::DidUpdateContent",
 512                        TRACE_EVENT_SCOPE_THREAD);
 513   clear_view_ = false;
 514   if (on_new_picture_enable_)
 515     client_->OnNewPicture();
 516 }
 517
 518 void BrowserViewRenderer::SetTotalRootLayerScrollOffset(
 519     gfx::Vector2dF scroll_offset_dip) {
 520   // TOOD(mkosiba): Add a DCHECK to say that this does _not_ get called during
 521   // DrawGl when http://crbug.com/249972 is fixed.
 522   if (scroll_offset_dip_ == scroll_offset_dip)
 523     return;
 524
 525   scroll_offset_dip_ = scroll_offset_dip;
 526
 527   gfx::Vector2d max_offset = max_scroll_offset();
 528   gfx::Vector2d scroll_offset;
 529   // For an explanation as to why this is done this way see the comment in
 530   // BrowserViewRenderer::ScrollTo.
 531   if (max_scroll_offset_dip_.x()) {
 532     scroll_offset.set_x((scroll_offset_dip.x() * max_offset.x()) /
 533                         max_scroll_offset_dip_.x());
 534   }
 535
 536   if (max_scroll_offset_dip_.y()) {
 537     scroll_offset.set_y((scroll_offset_dip.y() * max_offset.y()) /
 538                         max_scroll_offset_dip_.y());
 539   }
 540
 541   DCHECK_LE(0, scroll_offset.x());
 542   DCHECK_LE(0, scroll_offset.y());
 543   DCHECK_LE(scroll_offset.x(), max_offset.x());
 544   DCHECK_LE(scroll_offset.y(), max_offset.y());
 545
 546   client_->ScrollContainerViewTo(scroll_offset);
 547 }
 548
 549 gfx::Vector2dF BrowserViewRenderer::GetTotalRootLayerScrollOffset() {
 550   return scroll_offset_dip_;
 551 }
 552
 553 bool BrowserViewRenderer::IsExternalFlingActive() const {
 554   return client_->IsFlingActive();
 555 }
 556
 557 void BrowserViewRenderer::UpdateRootLayerState(
 558     const gfx::Vector2dF& total_scroll_offset_dip,
 559     const gfx::Vector2dF& max_scroll_offset_dip,
 560     const gfx::SizeF& scrollable_size_dip,
 561     float page_scale_factor,
 562     float min_page_scale_factor,
 563     float max_page_scale_factor) {
 564   TRACE_EVENT_INSTANT1(
 565       "android_webview",
 566       "BrowserViewRenderer::UpdateRootLayerState",
 567       TRACE_EVENT_SCOPE_THREAD,
 568       "state",
 569       RootLayerStateAsValue(total_scroll_offset_dip, scrollable_size_dip));
 570
 571   DCHECK_GT(dip_scale_, 0.f);
 572
 573   max_scroll_offset_dip_ = max_scroll_offset_dip;
 574   DCHECK_LE(0.f, max_scroll_offset_dip_.x());
 575   DCHECK_LE(0.f, max_scroll_offset_dip_.y());
 576
 577   page_scale_factor_ = page_scale_factor;
 578   DCHECK_GT(page_scale_factor_, 0.f);
 579
 580   client_->UpdateScrollState(max_scroll_offset(),
 581                              scrollable_size_dip,
 582                              page_scale_factor,
 583                              min_page_scale_factor,
 584                              max_page_scale_factor);
 585   SetTotalRootLayerScrollOffset(total_scroll_offset_dip);
 586 }
 587
 588 scoped_refptr<base::trace_event::ConvertableToTraceFormat>
 589 BrowserViewRenderer::RootLayerStateAsValue(
 590     const gfx::Vector2dF& total_scroll_offset_dip,
 591     const gfx::SizeF& scrollable_size_dip) {
 592   scoped_refptr<base::trace_event::TracedValue> state =
 593       new base::trace_event::TracedValue();
 594
 595   state->SetDouble("total_scroll_offset_dip.x", total_scroll_offset_dip.x());
 596   state->SetDouble("total_scroll_offset_dip.y", total_scroll_offset_dip.y());
 597
 598   state->SetDouble("max_scroll_offset_dip.x", max_scroll_offset_dip_.x());
 599   state->SetDouble("max_scroll_offset_dip.y", max_scroll_offset_dip_.y());
 600
 601   state->SetDouble("scrollable_size_dip.width", scrollable_size_dip.width());
 602   state->SetDouble("scrollable_size_dip.height", scrollable_size_dip.height());
 603
 604   state->SetDouble("page_scale_factor", page_scale_factor_);
 605   return state;
 606 }
 607
 608 void BrowserViewRenderer::DidOverscroll(gfx::Vector2dF accumulated_overscroll,
 609                                         gfx::Vector2dF latest_overscroll_delta,
 610                                         gfx::Vector2dF current_fling_velocity) {
 611   const float physical_pixel_scale = dip_scale_ * page_scale_factor_;
 612   if (accumulated_overscroll == latest_overscroll_delta)
 613     overscroll_rounding_error_ = gfx::Vector2dF();
 614   gfx::Vector2dF scaled_overscroll_delta =
 615       gfx::ScaleVector2d(latest_overscroll_delta, physical_pixel_scale);
 616   gfx::Vector2d rounded_overscroll_delta = gfx::ToRoundedVector2d(
 617       scaled_overscroll_delta + overscroll_rounding_error_);
 618   overscroll_rounding_error_ =
 619       scaled_overscroll_delta - rounded_overscroll_delta;
 620   client_->DidOverscroll(rounded_overscroll_delta);
 621 }
 622
 623 void BrowserViewRenderer::PostInvalidate() {
 624   TRACE_EVENT_INSTANT0("android_webview", "BrowserViewRenderer::PostInvalidate",
 625                        TRACE_EVENT_SCOPE_THREAD);
 626   PostInvalidateWithFallback();
 627 }
 628
 629 void BrowserViewRenderer::PostInvalidateWithFallback() {
 630   // Always call view invalidate. We rely the Android framework to ignore the
 631   // invalidate when it's not needed such as when view is not visible.
 632   client_->PostInvalidate();
 633
 634   // Stop fallback ticks when one of these is true.
 635   // 1) Webview is paused. Also need to check we are not in clear view since
 636   // paused, offscreen still expect clear view to recover.
 637   // 2) If we are attached to window and the window is not visible (eg when
 638   // app is in the background). We are sure in this case the webview is used
 639   // "on-screen" but that updates are not needed when in the background.
 640   bool throttle_fallback_tick =
 641       (is_paused_ && !clear_view_) || (attached_to_window_ && !window_visible_);
 642
 643   if (throttle_fallback_tick || fallback_tick_pending_)
 644     return;
 645
 646   DCHECK(post_fallback_tick_.IsCancelled());
 647   DCHECK(fallback_tick_fired_.IsCancelled());
 648
 649   post_fallback_tick_.Reset(base::Bind(&BrowserViewRenderer::PostFallbackTick,
 650                                        base::Unretained(this)));
 651   ui_task_runner_->PostTask(FROM_HERE, post_fallback_tick_.callback());
 652   fallback_tick_pending_ = true;
 653 }
 654
 655 void BrowserViewRenderer::CancelFallbackTick() {
 656   post_fallback_tick_.Cancel();
 657   fallback_tick_fired_.Cancel();
 658   fallback_tick_pending_ = false;
 659 }
 660
 661 void BrowserViewRenderer::PostFallbackTick() {
 662   DCHECK(fallback_tick_fired_.IsCancelled());
 663   TRACE_EVENT0("android_webview", "BrowserViewRenderer::PostFallbackTick");
 664   post_fallback_tick_.Cancel();
 665   fallback_tick_fired_.Reset(base::Bind(&BrowserViewRenderer::FallbackTickFired,
 666                                         base::Unretained(this)));
 667   ui_task_runner_->PostDelayedTask(
 668       FROM_HERE, fallback_tick_fired_.callback(),
 669       base::TimeDelta::FromMilliseconds(kFallbackTickTimeoutInMilliseconds));
 670 }
 671
 672 void BrowserViewRenderer::FallbackTickFired() {
 673   TRACE_EVENT0("android_webview", "BrowserViewRenderer::FallbackTickFired");
 674   // This should only be called if OnDraw or DrawGL did not come in time, which
 675   // means fallback_tick_pending_ must still be true.
 676   DCHECK(fallback_tick_pending_);
 677   fallback_tick_fired_.Cancel();
 678   fallback_tick_pending_ = false;
 679   if (compositor_) {
 680     if (hardware_enabled_) {
 681       CompositeHw();
 682     } else {
 683       ForceFakeCompositeSW();
 684     }
 685   }
 686 }
 687
 688 void BrowserViewRenderer::ForceFakeCompositeSW() {
 689   DCHECK(compositor_);
 690   SkBitmap bitmap;
 691   bitmap.allocN32Pixels(1, 1);
 692   bitmap.eraseColor(0);
 693   SkCanvas canvas(bitmap);
 694   CompositeSW(&canvas);
 695 }
 696
 697 bool BrowserViewRenderer::CompositeSW(SkCanvas* canvas) {
 698   DCHECK(compositor_);
 699   CancelFallbackTick();
 700   ReturnResourceFromParent();
 701   return compositor_->DemandDrawSw(canvas);
 702 }
 703
 704 void BrowserViewRenderer::UpdateCompositorIsActive() {
 705   if (compositor_)
 706     compositor_->SetIsActive(!is_paused_ &&
 707                              (!attached_to_window_ || window_visible_));
 708 }
 709
 710 std::string BrowserViewRenderer::ToString() const {
 711   std::string str;
 712   base::StringAppendF(&str, "is_paused: %d ", is_paused_);
 713   base::StringAppendF(&str, "view_visible: %d ", view_visible_);
 714   base::StringAppendF(&str, "window_visible: %d ", window_visible_);
 715   base::StringAppendF(&str, "dip_scale: %f ", dip_scale_);
 716   base::StringAppendF(&str, "page_scale_factor: %f ", page_scale_factor_);
 717   base::StringAppendF(&str, "fallback_tick_pending: %d ",
 718                       fallback_tick_pending_);
 719   base::StringAppendF(&str, "view size: %s ", size_.ToString().c_str());
 720   base::StringAppendF(&str, "attached_to_window: %d ", attached_to_window_);
 721   base::StringAppendF(&str,
 722                       "global visible rect: %s ",
 723                       last_on_draw_global_visible_rect_.ToString().c_str());
 724   base::StringAppendF(
 725       &str, "scroll_offset_dip: %s ", scroll_offset_dip_.ToString().c_str());
 726   base::StringAppendF(&str,
 727                       "overscroll_rounding_error_: %s ",
 728                       overscroll_rounding_error_.ToString().c_str());
 729   base::StringAppendF(
 730       &str, "on_new_picture_enable: %d ", on_new_picture_enable_);
 731   base::StringAppendF(&str, "clear_view: %d ", clear_view_);
 732   return str;
 733 }
 734
 735 }  // namespace android_webview