Fix focus and bounds calculations for guest frames.

content/browser/accessibility/browser_accessibility_cocoa.mm

Index: content/browser/accessibility/browser_accessibility_cocoa.mm
diff --git a/content/browser/accessibility/browser_accessibility_cocoa.mm b/content/browser/accessibility/browser_accessibility_cocoa.mm
index 92515d542894d31b8b2baa16a18ff8c17eb9871f..dd91619d4cf508c3e163827660a4ece3595b6ae4 100644
--- a/content/browser/accessibility/browser_accessibility_cocoa.mm
+++ b/content/browser/accessibility/browser_accessibility_cocoa.mm
@@ -25,6 +25,7 @@ extern "C" void NSAccessibilityUnregisterUniqueIdForUIElement(id element);
 
 using ui::AXNodeData;
 using content::BrowserAccessibility;
+using content::BrowserAccessibilityDelegate;
 using content::BrowserAccessibilityManager;
 using content::BrowserAccessibilityManagerMac;
 using content::ContentClient;
@@ -508,9 +509,22 @@ NSDictionary* attributeToMethodNameMap = nil;
   if (!browserAccessibility_)
     return NSZeroPoint;
 
-  gfx::Rect bounds(origin.x, origin.y, size.width, size.height);
-  gfx::Point point = [self delegate]->AccessibilityOriginInScreen(bounds);
-  return NSMakePoint(point.x(), point.y());
+  // Get the delegate for the topmost BrowserAccessibilityManager, because
+  // that's the only one that can convert points to their origin in the screen.
+  BrowserAccessibilityManager* manager = browserAccessibility_->manager();
+  BrowserAccessibility* root = manager->GetRoot();
+  while (root->GetParent())
+    root = root->GetParent()->manager()->GetRoot();
+  manager = root->manager();
+  BrowserAccessibilityDelegate* delegate = manager->delegate();
+
+  if (delegate) {
+    gfx::Rect bounds(origin.x, origin.y, size.width, size.height);
+    gfx::Point point = delegate->AccessibilityOriginInScreen(bounds);
+    return NSMakePoint(point.x(), point.y());
+  } else {
+    return NSZeroPoint;
+  }
 }
 
 // Returns a string indicating the NSAccessibility role of this object.