Add setting to isolate zoom changes by default.

components/zoom/zoom_controller.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 COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_
 #define COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
+#include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "components/prefs/pref_member.h"
 #include "content/public/browser/host_zoom_map.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
+#include "content/public/browser/zoom_level_delegate.h"
 
 class ZoomControllerTest;
+FORWARD_DECLARE_TEST(ZoomControllerTest, OnDefaultZoomScopeChanged);
+FORWARD_DECLARE_TEST(ZoomControllerPerTabTest, OnDefaultZoomScopeChanged);
 
 namespace content {
 class WebContents;
 }
 
 namespace zoom {
 class ZoomObserver;
 
 class ZoomRequestClient : public base::RefCounted<ZoomRequestClient> {
  public:
@@ skipping 11 matching lines @@
 
 // Per-tab class to manage zoom changes and the Omnibox zoom icon.
 class ZoomController : public content::WebContentsObserver,
                        public content::WebContentsUserData<ZoomController> {
  public:
   // Defines how zoom changes are handled.
   enum ZoomMode {
     // Results in default zoom behavior, i.e. zoom changes are handled
     // automatically and on a per-origin basis, meaning that other tabs
     // navigated to the same origin will also zoom.
+    // TODO Would we want to rename this?

[wjmaclean, 2017/01/19 21:09:05]

Nit: write as "TODO(<ldap>):"

[Kevin McNee, 2017/02/03 23:17:20]

Acknowledged.

     ZOOM_MODE_DEFAULT,
     // Results in zoom changes being handled automatically, but on a per-tab
     // basis. Tabs in this zoom mode will not be affected by zoom changes in
     // other tabs, and vice versa.
     ZOOM_MODE_ISOLATED,
     // Overrides the automatic handling of zoom changes. The |onZoomChange|
     // event will still be dispatched, but the page will not actually be zoomed.
     // These zoom changes can be handled manually by listening for the
     // |onZoomChange| event. Zooming in this mode is also on a per-tab basis.
     ZOOM_MODE_MANUAL,
@@ skipping 87 matching lines @@
   void SetPageScaleFactorIsOneForTesting(bool is_one);
   bool PageScaleFactorIsOne() const;
 
   // content::WebContentsObserver overrides:
   void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
       const content::FrameNavigateParams& params) override;
   void WebContentsDestroyed() override;
   void RenderFrameHostChanged(content::RenderFrameHost* old_host,
                               content::RenderFrameHost* new_host) override;
+  void DidCloneToNewWebContents(
+      content::WebContents* old_web_contents,
+      content::WebContents* new_web_contents) override;
+  void WebContentsReplaced(content::WebContents* old_web_contents,
+                           content::WebContents* new_web_contents) override;
 
  protected:
   // Protected for testing.
   explicit ZoomController(content::WebContents* web_contents);
 
  private:
   friend class content::WebContentsUserData<ZoomController>;
   friend class ::ZoomControllerTest;
+  FRIEND_TEST_ALL_PREFIXES(::ZoomControllerTest, OnDefaultZoomScopeChanged);
+  FRIEND_TEST_ALL_PREFIXES(::ZoomControllerPerTabTest,
+                           OnDefaultZoomScopeChanged);
 
   void ResetZoomModeOnNavigationIfNeeded(const GURL& url);
+  void UpdateZoomModeOnScopeChangeIfNeeded();
+  void PreserveTemporaryZoomLevel(content::WebContents* old_web_contents,
+                                  content::WebContents* new_web_contents) const;
   void OnZoomLevelChanged(const content::HostZoomMap::ZoomLevelChange& change);
+  void OnDefaultZoomScopeChanged();
 
   // Updates the zoom icon and zoom percentage based on current values and
   // notifies the observer if changes have occurred. |host| may be empty,
   // meaning the change should apply to ~all sites. If it is not empty, the
   // change only affects sites with the given host.
   void UpdateState(const std::string& host);
 
   // True if changes to zoom level can trigger the zoom notification bubble.
   bool can_show_bubble_;
 
   // The current zoom mode.
   ZoomMode zoom_mode_;
 
+  // Whether zoom changes are by default scoped to a page's origin.
+  // If false, they are scoped to the tab.
+  bool default_per_origin_;
+
   // Current zoom level.
   double zoom_level_;
 
   std::unique_ptr<ZoomChangedEventData> event_data_;
 
   // Keeps track of the extension (if any) that initiated the last zoom change
   // that took effect.
   scoped_refptr<const ZoomRequestClient> last_client_;
 
   // Observer receiving notifications on state changes.
   base::ObserverList<ZoomObserver> observers_;
 
   content::BrowserContext* browser_context_;
   // Keep track of the HostZoomMap we're currently subscribed to.
   content::HostZoomMap* host_zoom_map_;
 
   std::unique_ptr<content::HostZoomMap::Subscription> zoom_subscription_;
+  std::unique_ptr<content::ZoomLevelDelegate::DefaultZoomScopeSubscription>
+      default_zoom_scope_subscription_;
 
   DISALLOW_COPY_AND_ASSIGN(ZoomController);
 };
 
 }  // namespace zoom
 
 #endif  // COMPONENTS_ZOOM_ZOOM_CONTROLLER_H_