Implement caching asynchronous accessibility hit testing.

content/browser/accessibility/browser_accessibility.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.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 698 matching lines @@
         child_start += child_len;
         if (start >= child_len)
           start -= child_len;
         else
           start = -1;
       }
       return word_start;
   }
 }
 
-BrowserAccessibility* BrowserAccessibility::BrowserAccessibilityForPoint(
+BrowserAccessibility* BrowserAccessibility::ApproximateHitTest(
     const gfx::Point& point) {
   // The best result found that's a child of this object.
   BrowserAccessibility* child_result = NULL;
   // The best result that's an indirect descendant like grandchild, etc.
   BrowserAccessibility* descendant_result = NULL;
 
   // Walk the children recursively looking for the BrowserAccessibility that
   // most tightly encloses the specified point. Walk backwards so that in
   // the absence of any other information, we assume the object that occurs
   // later in the tree is on top of one that comes before it.
   for (int i = static_cast<int>(PlatformChildCount()) - 1; i >= 0; --i) {
     BrowserAccessibility* child = PlatformGetChild(i);
 
     // Skip table columns because cells are only contained in rows,
     // not columns.
     if (child->GetRole() == ui::AX_ROLE_COLUMN)
       continue;
 
     if (child->GetScreenBoundsRect().Contains(point)) {
-      BrowserAccessibility* result = child->BrowserAccessibilityForPoint(point);
+      BrowserAccessibility* result = child->ApproximateHitTest(point);
       if (result == child && !child_result)
         child_result = result;
       if (result != child && !descendant_result)
         descendant_result = result;
     }
 
     if (child_result && descendant_result)
       break;
   }
 
@@ skipping 466 matching lines @@
       }
     }
 
     node = container;
   }
 
   return gfx::ToEnclosingRect(bounds);
 }
 
 }  // namespace content