Block navigations in extensions via ShouldTransferNavigation (not via OpenURL).

content/browser/frame_host/navigator_delegate.h

 // Copyright 2013 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.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_
 
 #include "base/memory/scoped_vector.h"
 #include "base/strings/string16.h"
 #include "content/public/browser/invalidate_type.h"
@@ skipping 97 matching lines @@
   virtual void DidStartNavigationToPendingEntry(const GURL& url,
                                                 ReloadType reload_type) {}
 
   // Opens a URL with the given parameters. See PageNavigator::OpenURL, which
   // this forwards to.
   virtual void RequestOpenURL(RenderFrameHostImpl* render_frame_host,
                               const OpenURLParams& params) {}
 
   // Returns whether to continue a navigation that needs to transfer to a
   // different process between the load start and commit.
-  virtual bool ShouldTransferNavigation();
+  virtual bool ShouldTransferNavigation(bool is_main_frame_navigation);
 
   // Returns whether URLs for aborted browser-initiated navigations should be
   // preserved in the omnibox.  Defaults to false.
   virtual bool ShouldPreserveAbortedURLs();
 
   // A RenderFrameHost in the specified |frame_tree_node| started loading a new
   // document. This correponds to Blink's notion of the throbber starting.
   // |to_different_document| will be true unless the load is a fragment
   // navigation, or triggered by history.pushState/replaceState.
   virtual void DidStartLoading(FrameTreeNode* frame_tree_node,
                                bool to_different_document) {}
 
   // A document stopped loading. This corresponds to Blink's notion of the
   // throbber stopping.
   virtual void DidStopLoading() {}
 
   // The load progress was changed.
   virtual void DidChangeLoadProgress() {}
 
   // Returns the NavigationThrottles to add to this navigation. Normally these
   // are defined by the content/ embedder, except in the case of interstitials
   // where no NavigationThrottles are added to the navigation.
   virtual ScopedVector<NavigationThrottle> CreateThrottlesForNavigation(
       NavigationHandle* navigation_handle);
 };
 
 }  // namspace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_DELEGATE_H_