content/browser/accessibility/browser_accessibility_state_impl.cc

   1 // Copyright (c) 2012 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_state_impl.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/metrics/histogram.h"
   9 #include "base/timer/timer.h"
  10 #include "content/browser/accessibility/accessibility_mode_helper.h"
  11 #include "content/browser/renderer_host/render_widget_host_impl.h"
  12 #include "content/public/browser/browser_thread.h"
  13 #include "content/public/browser/render_process_host.h"
  14 #include "content/public/browser/render_widget_host_iterator.h"
  15 #include "content/public/common/content_switches.h"
  16 #include "ui/gfx/sys_color_change_listener.h"
  17
  18 #if defined(OS_WIN)
  19 #include "base/win/windows_version.h"
  20 #endif
  21
  22 namespace content {
  23
  24 // Update the accessibility histogram 45 seconds after initialization.
  25 static const int kAccessibilityHistogramDelaySecs = 45;
  26
  27 // static
  28 BrowserAccessibilityState* BrowserAccessibilityState::GetInstance() {
  29   return BrowserAccessibilityStateImpl::GetInstance();
  30 }
  31
  32 // static
  33 BrowserAccessibilityStateImpl* BrowserAccessibilityStateImpl::GetInstance() {
  34   return Singleton<BrowserAccessibilityStateImpl,
  35                    LeakySingletonTraits<BrowserAccessibilityStateImpl> >::get();
  36 }
  37
  38 BrowserAccessibilityStateImpl::BrowserAccessibilityStateImpl()
  39     : BrowserAccessibilityState(),
  40       accessibility_mode_(AccessibilityModeOff) {
  41   ResetAccessibilityModeValue();
  42 #if defined(OS_WIN)
  43   // On Windows, UpdateHistograms calls some system functions with unknown
  44   // runtime, so call it on the file thread to ensure there's no jank.
  45   // Everything in that method must be safe to call on another thread.
  46   BrowserThread::ID update_histogram_thread = BrowserThread::FILE;
  47 #else
  48   // On all other platforms, UpdateHistograms should be called on the main
  49   // thread.
  50   BrowserThread::ID update_histogram_thread = BrowserThread::UI;
  51 #endif
  52
  53   // We need to AddRef() the leaky singleton so that Bind doesn't
  54   // delete it prematurely.
  55   AddRef();
  56   BrowserThread::PostDelayedTask(
  57       update_histogram_thread, FROM_HERE,
  58       base::Bind(&BrowserAccessibilityStateImpl::UpdateHistograms, this),
  59       base::TimeDelta::FromSeconds(kAccessibilityHistogramDelaySecs));
  60 }
  61
  62 BrowserAccessibilityStateImpl::~BrowserAccessibilityStateImpl() {
  63 }
  64
  65 void BrowserAccessibilityStateImpl::OnScreenReaderDetected() {
  66   if (CommandLine::ForCurrentProcess()->HasSwitch(
  67           switches::kDisableRendererAccessibility)) {
  68     return;
  69   }
  70   EnableAccessibility();
  71 }
  72
  73 void BrowserAccessibilityStateImpl::EnableAccessibility() {
  74   AddAccessibilityMode(AccessibilityModeComplete);
  75 }
  76
  77 void BrowserAccessibilityStateImpl::DisableAccessibility() {
  78   ResetAccessibilityMode();
  79 }
  80
  81 void BrowserAccessibilityStateImpl::ResetAccessibilityModeValue() {
  82   accessibility_mode_ = AccessibilityModeOff;
  83 #if defined(OS_WIN)
  84   // On Windows 8, always enable accessibility for editable text controls
  85   // so we can show the virtual keyboard when one is enabled.
  86   if (base::win::GetVersion() >= base::win::VERSION_WIN8 &&
  87       !CommandLine::ForCurrentProcess()->HasSwitch(
  88           switches::kDisableRendererAccessibility)) {
  89     accessibility_mode_ = AccessibilityModeEditableTextOnly;
  90   }
  91 #endif  // defined(OS_WIN)
  92
  93   if (CommandLine::ForCurrentProcess()->HasSwitch(
  94           switches::kForceRendererAccessibility)) {
  95     accessibility_mode_ = AccessibilityModeComplete;
  96   }
  97 }
  98
  99 void BrowserAccessibilityStateImpl::ResetAccessibilityMode() {
 100   ResetAccessibilityModeValue();
 101
 102   // Iterate over all RenderWidgetHosts, even swapped out ones in case
 103   // they become active again.
 104   scoped_ptr<RenderWidgetHostIterator> widgets(
 105       RenderWidgetHostImpl::GetAllRenderWidgetHosts());
 106   while (RenderWidgetHost* widget = widgets->GetNextHost()) {
 107     // Ignore processes that don't have a connection, such as crashed tabs.
 108     if (!widget->GetProcess()->HasConnection())
 109       continue;
 110     if (!widget->IsRenderView())
 111       continue;
 112
 113     RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
 114     rwhi->ResetAccessibilityMode();
 115   }
 116 }
 117
 118 bool BrowserAccessibilityStateImpl::IsAccessibleBrowser() {
 119   return ((accessibility_mode_ & AccessibilityModeComplete) ==
 120           AccessibilityModeComplete);
 121 }
 122
 123 void BrowserAccessibilityStateImpl::AddHistogramCallback(
 124     base::Closure callback) {
 125   histogram_callbacks_.push_back(callback);
 126 }
 127
 128 void BrowserAccessibilityStateImpl::UpdateHistogramsForTesting() {
 129   UpdateHistograms();
 130 }
 131
 132 void BrowserAccessibilityStateImpl::UpdateHistograms() {
 133   UpdatePlatformSpecificHistograms();
 134
 135   for (size_t i = 0; i < histogram_callbacks_.size(); ++i)
 136     histogram_callbacks_[i].Run();
 137
 138   UMA_HISTOGRAM_BOOLEAN("Accessibility.State", IsAccessibleBrowser());
 139   UMA_HISTOGRAM_BOOLEAN("Accessibility.InvertedColors",
 140                         gfx::IsInvertedColorScheme());
 141   UMA_HISTOGRAM_BOOLEAN("Accessibility.ManuallyEnabled",
 142                         CommandLine::ForCurrentProcess()->HasSwitch(
 143                             switches::kForceRendererAccessibility));
 144 }
 145
 146 #if !defined(OS_WIN)
 147 void BrowserAccessibilityStateImpl::UpdatePlatformSpecificHistograms() {
 148 }
 149 #endif
 150
 151 void BrowserAccessibilityStateImpl::AddAccessibilityMode(
 152     AccessibilityMode mode) {
 153   if (CommandLine::ForCurrentProcess()->HasSwitch(
 154           switches::kDisableRendererAccessibility)) {
 155     return;
 156   }
 157
 158   accessibility_mode_ =
 159       content::AddAccessibilityModeTo(accessibility_mode_, mode);
 160
 161   AddOrRemoveFromRenderWidgets(mode, true);
 162 }
 163
 164 void BrowserAccessibilityStateImpl::RemoveAccessibilityMode(
 165     AccessibilityMode mode) {
 166   if (CommandLine::ForCurrentProcess()->HasSwitch(
 167           switches::kForceRendererAccessibility) &&
 168       mode == AccessibilityModeComplete) {
 169     return;
 170   }
 171
 172   accessibility_mode_ =
 173       content::RemoveAccessibilityModeFrom(accessibility_mode_, mode);
 174
 175   AddOrRemoveFromRenderWidgets(mode, false);
 176 }
 177
 178 void BrowserAccessibilityStateImpl::AddOrRemoveFromRenderWidgets(
 179     AccessibilityMode mode,
 180     bool add) {
 181   // Iterate over all RenderWidgetHosts, even swapped out ones in case
 182   // they become active again.
 183   scoped_ptr<RenderWidgetHostIterator> widgets(
 184       RenderWidgetHostImpl::GetAllRenderWidgetHosts());
 185   while (RenderWidgetHost* widget = widgets->GetNextHost()) {
 186     // Ignore processes that don't have a connection, such as crashed tabs.
 187     if (!widget->GetProcess()->HasConnection())
 188       continue;
 189     if (!widget->IsRenderView())
 190       continue;
 191
 192     RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
 193     if (add)
 194       rwhi->AddAccessibilityMode(mode);
 195     else
 196       rwhi->RemoveAccessibilityMode(mode);
 197   }
 198 }
 199
 200 }  // namespace content