Adds new experimental accessibility extension api to enable or disable native accessibility.

content/browser/accessibility/browser_accessibility_state_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/accessibility/browser_accessibility_state_impl.h"
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
 #include "base/timer.h"
+#include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
 #include "content/public/common/content_switches.h"
 #include "ui/gfx/sys_color_change_listener.h"
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
 #endif
 
 namespace content {
 
 // Update the accessibility histogram 45 seconds after initialization.
@@ skipping 52 matching lines @@
 }
 
 void BrowserAccessibilityStateImpl::OnScreenReaderDetected() {
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableRendererAccessibility)) {
     return;
   }
   SetAccessibilityMode(AccessibilityModeComplete);
 }
 
-void BrowserAccessibilityStateImpl::OnAccessibilityEnabledManually() {
+void BrowserAccessibilityStateImpl::OnAccessibilityEnabledByExtensionAPI() {
   // We may want to do something different with this later.
   SetAccessibilityMode(AccessibilityModeComplete);
 }
 
+void BrowserAccessibilityStateImpl::OnAccessibilityDisabledByExtensionAPI() {
+  SetAccessibilityMode(AccessibilityModeOff);
+}
+
 bool BrowserAccessibilityStateImpl::IsAccessibleBrowser() {
   return (accessibility_mode_ == AccessibilityModeComplete);
 }
 
 void BrowserAccessibilityStateImpl::AddHistogramCallback(
     base::Closure callback) {
   histogram_callbacks_.push_back(callback);
 }
 
 void BrowserAccessibilityStateImpl::UpdateHistogramsForTesting() {
@@ skipping 12 matching lines @@
   UMA_HISTOGRAM_BOOLEAN("Accessibility.ManuallyEnabled",
                         CommandLine::ForCurrentProcess()->HasSwitch(
                             switches::kForceRendererAccessibility));
 }
 
 #if !defined(OS_WIN)
 void BrowserAccessibilityStateImpl::UpdatePlatformSpecificHistograms() {
 }
 #endif
 
-AccessibilityMode BrowserAccessibilityStateImpl::GetAccessibilityMode() {
-  return accessibility_mode_;
-}
-
 void BrowserAccessibilityStateImpl::SetAccessibilityMode(
     AccessibilityMode mode) {
+  if (accessibility_mode_ == mode)
+    return;
   accessibility_mode_ = mode;
+  for (RenderProcessHost::iterator it(RenderProcessHost::AllHostsIterator());
+       !it.IsAtEnd(); it.Advance()) {
+    RenderProcessHost* render_process_host = it.GetCurrentValue();
+    DCHECK(render_process_host);
+
+    // Ignore processes that don't have a connection, such as crashed tabs.
+    if (!render_process_host->HasConnection())
+      continue;
+
+    RenderProcessHost::RenderWidgetHostsIterator rwit(

[sky, 2013/05/01 00:51:22]

nit: move into for loop (like you did on 131).

+        render_process_host->GetRenderWidgetHostsIterator());
+    for (; !rwit.IsAtEnd(); rwit.Advance()) {
+      RenderWidgetHost* rwh = const_cast<RenderWidgetHost*>(

[sky, 2013/05/01 00:51:22]

I'm not sure about the const_cast here.

[jam, 2013/05/01 05:19:17]

seems fine to me. i think it's a mistake that the iterator gives const pointers

+          rwit.GetCurrentValue());
+      DCHECK(rwh);
+      if (!rwh || !rwh->IsRenderView())
+        continue;
+      RenderWidgetHostImpl* rwhi = RenderWidgetHostImpl::From(rwh);
+      rwhi->SetAccessibilityMode(mode);
+    }
+  }
 }
 
 }  // namespace content