Enable renderer accessibility by default....

chrome/browser/renderer_host/render_widget_host.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_
 
 #include <deque>
+#include <string>
+#include <vector>
 
 #include "app/surface/transport_dib.h"
 #include "base/gtest_prod_util.h"
 #include "base/process.h"
 #include "base/scoped_ptr.h"
 #include "base/string16.h"
 #include "base/timer.h"
 #include "chrome/common/edit_command.h"
 #include "chrome/common/native_web_keyboard_event.h"
 #include "chrome/common/property_bag.h"
@@ skipping 344 matching lines @@
   // Makes an IPC call to tell webkit to replace the currently selected word
   // or a word around the cursor.
   void Replace(const string16& word);
 
   // Makes an IPC call to tell webkit to advance to the next misspelling.
   void AdvanceToNextMisspelling();
 
   // Requests a snapshot of an accessible DOM tree from the renderer.
   void RequestAccessibilityTree();
 
+  // Aid for determining when an accessibility tree request can be made. Set by
+  // TabContents to true on document load and to false on page nativigation.
+  void SetDocumentLoaded(bool document_loaded);
+
+  // Enable renderer accessibility. This should only be called when a
+  // screenreader is detected.
+  void EnableRendererAccessibility();
+
   // Relays a request from assistive technology to set focus to the
   // node with this accessibility object id.
   void SetAccessibilityFocus(int acc_obj_id);
 
   // Relays a request from assistive technology to perform the default action
   // on a node with this accessibility object id.
   void AccessibilityDoDefaultAction(int acc_obj_id);
 
   // Sets the active state (i.e., control tints).
   virtual void SetActive(bool active);
@@ skipping 140 matching lines @@
                        const gfx::Rect& bitmap_rect);
 
   // Called by OnMsgInputEventAck() to process a keyboard event ack message.
   void ProcessKeyboardEventAck(int type, bool processed);
 
   // Called by OnMsgInputEventAck() to process a wheel event ack message.
   // This could result in a task being posted to allow additional wheel
   // input messages to be coalesced.
   void ProcessWheelAck();
 
+  // True if renderer accessibility is enabled. This should only be set when a
+  // screenreader is detected as it can potentially slow down Chrome.
+  static bool renderer_accessible_;
+
   // The View associated with the RenderViewHost. The lifetime of this object
   // is associated with the lifetime of the Render process. If the Renderer
   // crashes, its View is destroyed and this pointer becomes NULL, even though
   // render_view_host_ lives on to load another URL (creating a new View while
   // doing so).
   RenderWidgetHostView* view_;
 
   // Created during construction but initialized during Init*(). Therefore, it
   // is guaranteed never to be NULL, but its channel may be NULL if the
   // renderer crashed, so you must always check that.
@@ skipping 117 matching lines @@
   // shall not send the following sequence of Char events, which was generated
   // by this RawKeyDown event, to the renderer. Otherwise the renderer may
   // handle the Char events and cause unexpected behavior.
   // For example, pressing alt-2 may let the browser switch to the second tab,
   // but the Char event generated by alt-2 may also activate a HTML element
   // if its accesskey happens to be "2", then the user may get confused when
   // switching back to the original tab, because the content may already be
   // changed.
   bool suppress_next_char_events_;
 
+  // Keep track of if we have a loaded document so that we can request an
+  // accessibility tree on demand when renderer accessibility is enabled.
+  bool document_loaded_;
+
+  // Keep track of if we've already requested the accessibility tree so
+  // we don't do it more than once.
+  bool requested_accessibility_tree_;
+
   // Optional video YUV layer for used for out-of-process compositing.
   scoped_ptr<VideoLayer> video_layer_;
 
   // Set to true if we want to wait until at least one more time through
   // the event loop to see if any additional wheel messages are coming in
   // before sending the coalesced ones.
   bool spin_runloop_before_sending_wheel_event_;
 
   // The time the last wheel message was sent to the renderer.
   base::TimeTicks last_wheel_message_time_;
 
   // For running tasks.
   ScopedRunnableMethodFactory<RenderWidgetHost> method_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHost);
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_H_