Refactor browser window zoom handling and enable zoom icon on all platforms.

chrome/browser/ui/cocoa/browser_window_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 CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_H_
 #define CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_H_
 
 // A class acting as the Objective-C controller for the Browser
 // object. Handles interactions between Cocoa and the cross-platform
 // code. Each window has a single toolbar and, by virtue of being a
@@ skipping 205 matching lines @@
 // Updates the toolbar (and transitively the location bar) with the states of
 // the specified |tab|.  If |shouldRestore| is true, we're switching
 // (back?) to this tab and should restore any previous location bar state
 // (such as user editing) as well.
 - (void)updateToolbarWithContents:(content::WebContents*)tab
                shouldRestoreState:(BOOL)shouldRestore;
 
 // Sets whether or not the current page in the frontmost tab is bookmarked.
 - (void)setStarredState:(BOOL)isStarred;
 
+// Happens when the zoom level is changed in the active tab, the active tab is
+// changed, or a new browser window or tab is created. |canShowBubble| denotes
+// whether it would be appropriate to show a zoom bubble or not.
+- (void)zoomChangedForActiveTab:(BOOL)canShowBubble;
+
 // Return the rect, in WebKit coordinates (flipped), of the window's grow box
 // in the coordinate system of the content area of the currently selected tab.
 - (NSRect)selectedTabGrowBoxRect;
 
 // Called to tell the selected tab to update its loading state.
 // |force| is set if the update is due to changing tabs, as opposed to
 // the page-load finishing.  See comment in reload_button.h.
 - (void)setIsLoading:(BOOL)isLoading force:(BOOL)force;
 
 // Brings this controller's window to the front.
@@ skipping 246 matching lines @@
 // |source| rect doesn't fit into |target|.
 - (NSSize)overflowFrom:(NSRect)source
                     to:(NSRect)target;
 
 // The fullscreen exit bubble controller, or nil if the bubble isn't showing.
 - (FullscreenExitBubbleController*)fullscreenExitBubbleController;
 @end  // @interface BrowserWindowController (TestingAPI)
 
 
 #endif  // CHROME_BROWSER_UI_COCOA_BROWSER_WINDOW_CONTROLLER_H_