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