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..27bcf8aa55aed90bfb213ddb6e20db6ae0f416dc 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;
@@ -508,8 +509,17 @@ NSDictionary* attributeToMethodNameMap = nil;
   if (!browserAccessibility_)
     return NSZeroPoint;
 
+  // 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();

[aboxhall, 2015/01/15 05:08:25]

That's an impressive method chain! Any chance of any nulls in here? (I guess,
any chance of manager() or GetRoot() returning null.)

[dmazzoni, 2015/01/15 21:02:33]

Great question!
* root->GetParent() can't be NULL because of the loop condition
* a BrowserAccessibility object is always owned by a
BrowserAccessibilityManager; it's never NULL
* A BrowserAccessibilityManager always has a root, it's never NULL

So we're okay.

However, manager->delegate() may be NULL, so I'll fix that below.

+  manager = root->manager();
+  BrowserAccessibilityDelegate* delegate = manager->delegate();
+
   gfx::Rect bounds(origin.x, origin.y, size.width, size.height);
-  gfx::Point point = [self delegate]->AccessibilityOriginInScreen(bounds);
+  gfx::Point point = delegate->AccessibilityOriginInScreen(bounds);
   return NSMakePoint(point.x(), point.y());
 }