Reimplement accessibility of web content by caching the entire

accessibility tree in the browser process.

Adds new RPCs for a browser tab to request accessibility info from
a renderer; the renderer responds with a complete tree of
accessibility metadata for the entire DOM, which is then cached
in the RenderWidgetHostView. This part is cross-platform and will
help with accessibility on both Windows and Mac OS X.

For Windows, MSAA support for web content has been rewritten to
use this new cache. Tested in JAWS and NVDA screen readers.
Using Chrome with a screen reader is now fast and stable,
unlike the previous implementation. However, note that most
advanced functionality is still not supported, and much work remains
to make Chrome work well with a screen reader. This is a necessary
step to improve stability first.

BUG=25564
BUG=13291
TEST=See http://codereview.chromium.org/1806001

Review URL: http://codereview.chromium.org/1637018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@46916 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 9 insertions, 0 deletions

diff --git a/chrome/browser/tab_contents/tab_contents.h b/chrome/browser/tab_contents/tab_contents.h
index e9465cf..78465ec 100644
--- a/chrome/browser/tab_contents/tab_contents.h
+++ b/chrome/browser/tab_contents/tab_contents.h
@@ -1260,6 +1260,15 @@ class TabContents : public PageNavigator,
   // Manages information about Geolocation API usage in this page.
   GeolocationSettingsState geolocation_settings_state_;
 
+  // Whether the renderer is made accessible.
+  // TODO(dmazzoni): http://crbug.com/25564 This is a temporary work-around
+  // until that bug is fixed.
+  bool renderer_accessible_;
+
+  // Keep track of if we've already requested the accessibility tree so
+  // we don't do it more than once.
+  bool requested_accessibility_tree_;
+
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);