Changes to content/ to facilitate new zoom extension API

content/public/browser/web_contents_observer.h

 // Copyright (c) 2012 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_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/process/kill.h"
 #include "base/process/process_handle.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "content/public/common/page_transition_types.h"
+#include "content/public/common/page_zoom.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "ui/base/window_open_disposition.h"
 
 namespace content {
 
 class NavigationEntry;
 class RenderFrameHost;
 class RenderViewHost;
 class WebContents;
@@ skipping 288 matching lines @@
   // Invoked when the renderer has toggled the tab into/out of fullscreen mode.
   virtual void DidToggleFullscreenModeForTab(bool entered_fullscreen) {}
 
   // Invoked when visible SSL state (as defined by SSLStatus) changes.
   virtual void DidChangeVisibleSSLState() {}
 
   // Invoked when an interstitial page is attached or detached.
   virtual void DidAttachInterstitialPage() {}
   virtual void DidDetachInterstitialPage() {}
 
+  // Invoked when a zoom change is initiated from WebContents::SetZoomLevel().
+  virtual void DidSetZoomLevel(int old_zoom_level,
+                               int new_zoom_level,
+                               ZoomMode zoom_mode) {}

[jam, 2014/04/10 21:45:45]

see http://www.chromium.org/developers/content-module/content-api, specifically:

"methods in the API should be there because either content is calling out to its
embedder, or the embedder is calling to content. There shouldn't be any methods
which are used to call from the embedder to the embedder."

since the chrome layer is calling WebContents::SetZoomLevel, we shouldn't have
to tell it back again that it did. whatever code it needs to be done as a result
it should do at the callsites.

+
   // Invoked before a form repost warning is shown.
   virtual void BeforeFormRepostWarningShow() {}
 
   // Invoked when the beforeunload handler fires. The time is from the renderer.
   virtual void BeforeUnloadFired(const base::TimeTicks& proceed_time) {}
 
   // Invoked when a user cancels a before unload dialog.
   virtual void BeforeUnloadDialogCancelled() {}
 
   // Invoked when an accessibility event is received from the renderer.
@@ skipping 32 matching lines @@
   void WebContentsImplDestroyed();
 
   WebContentsImpl* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_