Disable zoom bubble for PDF extension.

extensions/browser/extension_zoom_request_client.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_EXTENSION_ZOOM_REQUEST_CLIENT_H_
 #define EXTENSIONS_BROWSER_EXTENSION_ZOOM_REQUEST_CLIENT_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "components/ui/zoom/zoom_controller.h"
 #include "extensions/common/extension.h"
 
 namespace extensions {
 
 class Extension;
 
 // This class implements ZoomRequestClient in order to encapsulate a ref pointer
 // back to an extension requesting a zoom level change. This is important so
 // that zoom event observers can determine if an extension made the request
 // as opposed to direct user input.
 class ExtensionZoomRequestClient : public ui_zoom::ZoomRequestClient {
  public:
   explicit ExtensionZoomRequestClient(scoped_refptr<const Extension> extension);
 
+  bool ShouldSuppressBubble() const override;
   const Extension* extension() const { return extension_.get(); }
 
  private:
   ~ExtensionZoomRequestClient() override;
   scoped_refptr<const Extension> extension_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionZoomRequestClient);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_EXTENSION_ZOOM_REQUEST_CLIENT_H_