Return the outermost embedder when returning the embedder web contents.

chrome/browser/ui/views/chrome_constrained_window_views_client.cc

 // Copyright 2014 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/browser/ui/views/chrome_constrained_window_views_client.h"
 
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 #include "extensions/browser/guest_view/guest_view_base.h"
 
 namespace {
 
 class ChromeConstrainedWindowViewsClient
     : public constrained_window::ConstrainedWindowViewsClient {
  public:
   ChromeConstrainedWindowViewsClient() {}
   ~ChromeConstrainedWindowViewsClient() override {}
 
  private:
   // ConstrainedWindowViewsClient:
   content::WebContents* GetEmbedderWebContents(
       content::WebContents* initiator_web_contents) override {
-    extensions::GuestViewBase* guest_view =
-        extensions::GuestViewBase::FromWebContents(initiator_web_contents);
-    return guest_view && guest_view->embedder_web_contents() ?
-        guest_view->embedder_web_contents() : initiator_web_contents;
+    // |initiator_web_contents| may be embedded within a chain of nested
+    // GuestViews. If it is, follow the chain of embedders to the outermost
+    // WebContents and return it.
+    while (extensions::GuestViewBase* guest_view =
+               extensions::GuestViewBase::FromWebContents(
+                   initiator_web_contents)) {
+      if (!guest_view->embedder_web_contents())
+        break;
+      initiator_web_contents = guest_view->embedder_web_contents();
+    }
+    return initiator_web_contents;
   }
   web_modal::ModalDialogHost* GetModalDialogHost(
       gfx::NativeWindow parent) override {
     // Get the browser dialog management and hosting components from |parent|.
     Browser* browser = chrome::FindBrowserWithWindow(parent);
     if (browser) {
       ChromeWebModalDialogManagerDelegate* manager = browser;
       return manager->GetWebContentsModalDialogHost();
     }
     return nullptr;
   }
   gfx::NativeView GetDialogHostView(gfx::NativeWindow parent) override {
     return platform_util::GetViewForWindow(parent);
   }
 
   DISALLOW_COPY_AND_ASSIGN(ChromeConstrainedWindowViewsClient);
 };
 
 }  // namespace
 
 scoped_ptr<constrained_window::ConstrainedWindowViewsClient>
 CreateChromeConstrainedWindowViewsClient() {
   return make_scoped_ptr(new ChromeConstrainedWindowViewsClient);
 }