Only inject the HTML titlebar into toplevel frames.

chrome/renderer/extensions/app_window_custom_bindings.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 "chrome/renderer/extensions/app_window_custom_bindings.h"
 
 #include <string>
 
 #include "chrome/common/extensions/extension_messages.h"
 #include "chrome/renderer/extensions/chrome_v8_context.h"
 #include "chrome/renderer/extensions/dispatcher.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/public/renderer/render_view.h"
 #include "content/public/renderer/render_view_observer.h"
 #include "content/public/renderer/render_view_visitor.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
 #include "v8/include/v8.h"
 
 namespace extensions {
 
 class DidCreateDocumentElementObserver : public content::RenderViewObserver {
  public:
   DidCreateDocumentElementObserver(
       content::RenderView* view, Dispatcher* dispatcher)
       : content::RenderViewObserver(view), dispatcher_(dispatcher) {
   }
 
   virtual void DidCreateDocumentElement(WebKit::WebFrame* frame) OVERRIDE {
-    v8::HandleScope handle_scope;
     DCHECK(frame);
     DCHECK(dispatcher_);
+    // Don't attempt to inject the titlebar into iframes.
+    if (frame->parent())
+      return;
+    v8::HandleScope handle_scope;
     ChromeV8Context* v8_context =
         dispatcher_->v8_context_set().GetByV8Context(
             frame->mainWorldScriptContext());
 
     if (!v8_context)
       return;
     v8::Context::Scope context_scope(v8_context->v8_context());
     v8_context->module_system()->CallModuleMethod(
         "injectAppTitlebar", "didCreateDocumentElement");
   }
@@ skipping 77 matching lines @@
   WebKit::WebFrame* frame = view->GetWebView()->mainFrame();
   frame->setOpener(opener);
   content::RenderThread::Get()->Send(
       new ExtensionHostMsg_ResumeRequests(view->GetRoutingID()));
 
   v8::Local<v8::Value> window = frame->mainWorldScriptContext()->Global();
   return window;
 }
 
 }  // namespace extensions