Reimplement web content accessibility by caching in browser process

chrome/common/render_messages_internal.h

Index: chrome/common/render_messages_internal.h
===================================================================
--- chrome/common/render_messages_internal.h	(revision 46908)
+++ chrome/common/render_messages_internal.h	(working copy)
@@ -512,20 +512,6 @@
   // Used to instruct the RenderView to go into "view source" mode.
   IPC_MESSAGE_ROUTED0(ViewMsg_EnableViewSourceMode)
 
-  // Retreive information from the MSAA DOM subtree, for accessibility purposes.
-  IPC_SYNC_MESSAGE_ROUTED1_1(ViewMsg_GetAccessibilityInfo,
-                             webkit_glue::WebAccessibility::InParams
-                             /* input parameters */,
-                             webkit_glue::WebAccessibility::OutParams
-                             /* output parameters */)
-
-  // Requests the renderer to clear cashed accessibility information. Takes an
-  // id to clear a specific hashmap entry, and a bool; true clears all, false
-  // does not.
-  IPC_MESSAGE_ROUTED2(ViewMsg_ClearAccessibilityInfo,
-                      int  /* accessibility object id */,
-                      bool /* clear_all */)
-
   // Get all savable resource links from current webpage, include main
   // frame and sub-frame.
   IPC_MESSAGE_ROUTED1(ViewMsg_GetAllSavableResourceLinksForCurrentPage,
@@ -943,6 +929,9 @@
   // Notification that the list of extensions with web extents has been updated.
   IPC_MESSAGE_CONTROL1(ViewMsg_ExtensionExtentsUpdated,
                        ViewMsg_ExtensionExtentsUpdated_Params)
+
+  // Request a tree of Accessibility data from the render process.
+  IPC_MESSAGE_ROUTED0(ViewMsg_GetAccessibilityTree)
 IPC_END_MESSAGES(View)
 
 
@@ -2344,4 +2333,9 @@
                        int /* render_view_id */,
                        int /* bridge_id */)
 
+  // Send the tree of accessibility data to the browser, where it's cached
+  // in order to respond to OS accessibility queries immediately.
+  IPC_MESSAGE_ROUTED1(ViewHostMsg_AccessibilityTree,
+                      webkit_glue::WebAccessibility)
+
 IPC_END_MESSAGES(ViewHost)