Use FrameTreeNode ID as frameId in extension APIs

content/browser/frame_host/render_frame_host_impl.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_RENDER_FRAME_HOST_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_
 
 #include <map>
 #include <vector>
 
@@ skipping 100 matching lines @@
   // Helper function to determine whether the RFH state should contribute to the
   // number of active frames of a SiteInstance or not.
   static bool IsRFHStateActive(RenderFrameHostImplState rfh_state);
 
   // An accessibility reset is only allowed to prevent very rare corner cases
   // or race conditions where the browser and renderer get out of sync. If
   // this happens more than this many times, kill the renderer.
   static const int kMaxAccessibilityResets = 5;
 
   static RenderFrameHostImpl* FromID(int process_id, int routing_id);
+  static RenderFrameHostImpl* FromFrameTreeNodeID(int frame_tree_node_id);
   static RenderFrameHostImpl* FromAXTreeID(
       AXTreeIDRegistry::AXTreeID ax_tree_id);
 
   ~RenderFrameHostImpl() override;
 
   // RenderFrameHost
   int GetRoutingID() override;
   AXTreeIDRegistry::AXTreeID GetAXTreeID() override;
   SiteInstanceImpl* GetSiteInstance() override;
   RenderProcessHost* GetProcess() override;
   RenderFrameHost* GetParent() override;
+  RenderFrameHost* FindByFrameTreeNodeID(int frame_tree_node_id) override;
+  int GetFrameTreeNodeID() override;
   const std::string& GetFrameName() override;
   bool IsCrossProcessSubframe() override;
   GURL GetLastCommittedURL() override;
   gfx::NativeView GetNativeView() override;
   void AddMessageToConsole(ConsoleMessageLevel level,
                            const std::string& message) override;
   void ExecuteJavaScript(const base::string16& javascript) override;
   void ExecuteJavaScript(const base::string16& javascript,
                          const JavaScriptResultCallback& callback) override;
   void ExecuteJavaScriptForTests(const base::string16& javascript) override;
@@ skipping 650 matching lines @@
 
   // NOTE: This must be the last member.
   base::WeakPtrFactory<RenderFrameHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_IMPL_H_