Forward BrowserAccessibility::accHitTest to AXPlatformNode.

ui/accessibility/platform/ax_platform_node_win.cc

 // Copyright 2015 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 <atlbase.h>
 #include <atlcom.h>
 #include <limits.h>
 #include <oleacc.h>
 #include <stdint.h>
 
@@ skipping 260 matching lines @@
   return -1;
 }
 
 //
 // IAccessible implementation.
 //
 
 STDMETHODIMP AXPlatformNodeWin::accHitTest(
     LONG x_left, LONG y_top, VARIANT* child) {
   COM_OBJECT_VALIDATE_1_ARG(child);
+
+  gfx::Point point(x_left, y_top);
+  if (!delegate_->GetScreenBoundsRect().Contains(point)) {
+    // Return S_FALSE and VT_EMPTY when outside the object's boundaries.
+    child->vt = VT_EMPTY;
+    return S_FALSE;
+  }
+
   gfx::NativeViewAccessible hit_child = delegate_->HitTestSync(x_left, y_top);
   if (!hit_child) {
     child->vt = VT_EMPTY;
     return S_FALSE;
   }
 
   if (hit_child == this) {
     // This object is the best match, so return CHILDID_SELF. It's tempting to
     // simplify the logic and use VT_DISPATCH everywhere, but the Windows
     // call AccessibleObjectFromPoint will keep calling accHitTest until some
@@ skipping 1408 matching lines @@
 
   AXPlatformNodeBase* base =
       FromNativeViewAccessible(node->GetNativeViewAccessible());
   if (base && !IsDescendant(base))
     base = nullptr;
 
   return static_cast<AXPlatformNodeWin*>(base);
 }
 
 }  // namespace ui