Implement signin using webview

extensions/browser/guest_view/guest_view_base.h

 // 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.
 
 #ifndef EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 #define EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 
 #include <queue>
 
 #include "base/memory/weak_ptr.h"
@@ skipping 69 matching lines @@
   // This method is called after this GuestViewBase has been initiated.
   //
   // This gives the derived class an opportunity to perform additional
   // initialization.
   virtual void DidInitialize() {}
 
   // This method is called when the initial set of frames within the page have
   // completed loading.
   virtual void DidStopLoading() {}
 
+  // This method is called before the guest will be detached from its embedder.
+  // |embedder_web_contents_| should still be valid during this call. This
+  // allows the derived class to perform some cleanup related to the embedder
+  // web contents.
+  virtual void WillDetachFromEmbedder() {}
+
   // This method is called when the guest's embedder WebContents has been
   // destroyed and the guest will be destroyed shortly.
   //
   // This gives the derived class an opportunity to perform some cleanup prior
   // to destruction.
   virtual void EmbedderDestroyed() {}
 
   // This method is called when the guest WebContents has been destroyed. This
   // object will be destroyed after this call returns.
   //
@@ skipping 227 matching lines @@
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
   base::WeakPtrFactory<GuestViewBase> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GuestViewBase);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_