Fix accessibility objects with zero width and height.

content/browser/accessibility/browser_accessibility.h

Index: content/browser/accessibility/browser_accessibility.h
diff --git a/content/browser/accessibility/browser_accessibility.h b/content/browser/accessibility/browser_accessibility.h
index 643e5950d5a485afbea2450a8fb6224ada79a7f6..27f6a74c8b2f0919b13b15aae19f6a4ed4cec720 100644
--- a/content/browser/accessibility/browser_accessibility.h
+++ b/content/browser/accessibility/browser_accessibility.h
@@ -283,6 +283,12 @@ class CONTENT_EXPORT BrowserAccessibility {
   // bounds offsets.
   BrowserAccessibility* GetParentForBoundsCalculation() const;
 
+  // If a bounding rectangle is empty, compute it based on the union of its
+  // children, since most accessibility APIs don't like elements with no
+  // bounds, but "virtual" elements in the accessibility tree that don't
+  // correspond to a layed-out element sometimes don't have bounds.

[David Tseng, 2015/06/22 21:29:36]

What happens if there are multiple levels of empty virtual nodes?

[dmazzoni, 2015/06/23 05:36:42]

It calls GetLocalBoundsRect on each child, which calls FixEmptyBounds - so it
should work correctly with multiple levels of empty virtual nodes too. 

[David Tseng, 2015/06/23 18:27:53]

Ok got it; it's alternating recursively calling
FixEmptyBounds/GetLocalBoundsRect.

+  void FixEmptyBounds(gfx::Rect* bounds) const;
+
   // Convert the bounding rectangle of an element (which is relative to
   // its nearest scrollable ancestor) to local bounds (which are relative
   // to the top of the web accessibility tree).