Add setting to isolate zoom changes by default.

content/public/browser/host_zoom_map.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_HOST_ZOOM_MAP_H_
 #define CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/callback_list.h"
 #include "content/common/content_export.h"
 #include "url/gurl.h"
 
 namespace content {
 
 class NavigationEntry;
 class BrowserContext;
+class RenderFrameHost;
 class SiteInstance;
 class WebContents;
 
 // Maps hostnames to custom zoom levels.  Written on the UI thread and read on
 // any thread.  One instance per browser context. Must be created on the UI
 // thread, and it'll delete itself on the UI thread as well.
 // Zoom can be defined at three levels: default zoom, zoom for host, and zoom
 // for host with specific scheme. Setting any of the levels leaves settings
 // for other settings intact. Getting the zoom level starts at the most
 // specific setting and progresses to the less specific: first the zoom for the
@@ skipping 63 matching lines @@
   // Set or clear whether or not the page scale factor for a view is one.
   virtual void SetPageScaleFactorIsOneForView(
       int render_process_id, int render_view_id, bool is_one) = 0;
   virtual void ClearPageScaleFactorIsOneForView(
       int render_process_id, int render_view_id) = 0;
 
   // Copy the zoom levels from the given map. Can only be called on the UI
   // thread.
   virtual void CopyFrom(HostZoomMap* copy) = 0;
 
+  // Copy the temporary zoom level entry of |old_host| from the given map to
+  // this map's entry for |new_host|.
+  virtual void PreserveTemporaryZoomLevelFrom(
+      const HostZoomMap* copy, RenderFrameHost* old_host,
+      RenderFrameHost* new_host) = 0;
+
   // Here |host| is the host portion of URL, or (in the absence of a host)
   // the complete spec of the URL.
   // Returns the zoom for the specified |scheme| and |host|. See class
   // description for details.
   //
   // This may be called on any thread.
   virtual double GetZoomLevelForHostAndScheme(
       const std::string& scheme,
       const std::string& host) const = 0;
 
@@ skipping 26 matching lines @@
   // This should only be called on the UI thread.
   virtual void SetZoomLevelForHostAndScheme(const std::string& scheme,
                                             const std::string& host,
                                             double level) = 0;
 
   // Returns whether the view manages its zoom level independently of other
   // views displaying content from the same host.
   virtual bool UsesTemporaryZoomLevel(int render_process_id,
                                       int render_view_id) const = 0;
 
-  // Sets the temporary zoom level that's only valid for the lifetime of this
-  // WebContents.
+  // Sets the temporary zoom level that's only valid for the lifetime of the
+  // given view.
   //
   // This should only be called on the UI thread.
   virtual void SetTemporaryZoomLevel(int render_process_id,
                                      int render_view_id,
                                      double level) = 0;
 
-  // Clears the temporary zoom level stored for this WebContents.
+  // Clears the temporary zoom level stored for the given view.
   //
   // This should only be called on the UI thread.
   virtual void ClearTemporaryZoomLevel(int render_process_id,
                                        int render_view_id) = 0;
 
   // Get/Set the default zoom level for pages that don't override it.
   virtual double GetDefaultZoomLevel() const = 0;
   virtual void SetDefaultZoomLevel(double level) = 0;
 
   typedef base::Callback<void(const ZoomLevelChange&)> ZoomLevelChangedCallback;
   typedef base::CallbackList<void(const ZoomLevelChange&)>::Subscription
       Subscription;
   // Add and remove zoom level changed callbacks.
   virtual std::unique_ptr<Subscription> AddZoomLevelChangedCallback(
       const ZoomLevelChangedCallback& callback) = 0;
 
  protected:
   virtual ~HostZoomMap() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_HOST_ZOOM_MAP_H_