src/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   AddAccessibilityMode(AccessibilityModeComplete);
  67 }
  68
  69 void BrowserAccessibilityStateImpl::EnableAccessibility() {
  70   // We may want to do something different with this later.
  71   AddAccessibilityMode(AccessibilityModeComplete);
  72 }
  73
  74 void BrowserAccessibilityStateImpl::DisableAccessibility() {
  75   ResetAccessibilityMode();
  76 }
  77
  78 void BrowserAccessibilityStateImpl::ResetAccessibilityModeValue() {
  79   accessibility_mode_ = AccessibilityModeOff;
  80 #if defined(OS_WIN)
  81   // On Windows 8, always enable accessibility for editable text controls
  82   // so we can show the virtual keyboard when one is enabled.
  83   if (base::win::GetVersion() >= base::win::VERSION_WIN8 &&
  84       !CommandLine::ForCurrentProcess()->HasSwitch(
  85           switches::kDisableRendererAccessibility)) {
  86     accessibility_mode_ = AccessibilityModeEditableTextOnly;
  87   }
  88 #endif  // defined(OS_WIN)
  89
  90   if (CommandLine::ForCurrentProcess()->HasSwitch(
  91           switches::kForceRendererAccessibility)) {
  92     accessibility_mode_ = AccessibilityModeComplete;
  93   }
  94 }
  95
  96 void BrowserAccessibilityStateImpl::ResetAccessibilityMode() {
  97   ResetAccessibilityModeValue();
  98
  99   // Iterate over all RenderWidgetHosts, even swapped out ones in case
 100   // they become active again.
 101   scoped_ptr<RenderWidgetHostIterator> widgets(
 102       RenderWidgetHostImpl::GetAllRenderWidgetHosts());
 103   while (RenderWidgetHost* widget = widgets->GetNextHost()) {
 104     // Ignore processes that don't have a connection, such as crashed tabs.
 105     if (!widget->GetProcess()->HasConnection())
 106       continue;
 107     if (!widget->IsRenderView())
 108       continue;
 109
 110     RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
 111     rwhi->ResetAccessibilityMode();
 112   }
 113 }
 114
 115 bool BrowserAccessibilityStateImpl::IsAccessibleBrowser() {
 116   return ((accessibility_mode_ & AccessibilityModeComplete) ==
 117           AccessibilityModeComplete);
 118 }
 119
 120 void BrowserAccessibilityStateImpl::AddHistogramCallback(
 121     base::Closure callback) {
 122   histogram_callbacks_.push_back(callback);
 123 }
 124
 125 void BrowserAccessibilityStateImpl::UpdateHistogramsForTesting() {
 126   UpdateHistograms();
 127 }
 128
 129 void BrowserAccessibilityStateImpl::UpdateHistograms() {
 130   UpdatePlatformSpecificHistograms();
 131
 132   for (size_t i = 0; i < histogram_callbacks_.size(); ++i)
 133     histogram_callbacks_[i].Run();
 134
 135   UMA_HISTOGRAM_BOOLEAN("Accessibility.State", IsAccessibleBrowser());
 136   UMA_HISTOGRAM_BOOLEAN("Accessibility.InvertedColors",
 137                         gfx::IsInvertedColorScheme());
 138   UMA_HISTOGRAM_BOOLEAN("Accessibility.ManuallyEnabled",
 139                         CommandLine::ForCurrentProcess()->HasSwitch(
 140                             switches::kForceRendererAccessibility));
 141 }
 142
 143 #if !defined(OS_WIN)
 144 void BrowserAccessibilityStateImpl::UpdatePlatformSpecificHistograms() {
 145 }
 146 #endif
 147
 148 void BrowserAccessibilityStateImpl::AddAccessibilityMode(
 149     AccessibilityMode mode) {
 150   if (CommandLine::ForCurrentProcess()->HasSwitch(
 151           switches::kDisableRendererAccessibility)) {
 152     return;
 153   }
 154
 155   accessibility_mode_ =
 156       content::AddAccessibilityModeTo(accessibility_mode_, mode);
 157
 158   AddOrRemoveFromRenderWidgets(mode, true);
 159 }
 160
 161 void BrowserAccessibilityStateImpl::RemoveAccessibilityMode(
 162     AccessibilityMode mode) {
 163   if (CommandLine::ForCurrentProcess()->HasSwitch(
 164           switches::kForceRendererAccessibility) &&
 165       mode == AccessibilityModeComplete) {
 166     return;
 167   }
 168
 169   accessibility_mode_ =
 170       content::RemoveAccessibilityModeFrom(accessibility_mode_, mode);
 171
 172   AddOrRemoveFromRenderWidgets(mode, false);
 173 }
 174
 175 void BrowserAccessibilityStateImpl::AddOrRemoveFromRenderWidgets(
 176     AccessibilityMode mode,
 177     bool add) {
 178   // Iterate over all RenderWidgetHosts, even swapped out ones in case
 179   // they become active again.
 180   scoped_ptr<RenderWidgetHostIterator> widgets(
 181       RenderWidgetHostImpl::GetAllRenderWidgetHosts());
 182   while (RenderWidgetHost* widget = widgets->GetNextHost()) {
 183     // Ignore processes that don't have a connection, such as crashed tabs.
 184     if (!widget->GetProcess()->HasConnection())
 185       continue;
 186     if (!widget->IsRenderView())
 187       continue;
 188
 189     RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(widget);
 190     if (add)
 191       rwhi->AddAccessibilityMode(mode);
 192     else
 193       rwhi->RemoveAccessibilityMode(mode);
 194   }
 195 }
 196
 197 }  // namespace content