Tracks changes to zoom icon and zoom percentage. Notifies browser window if the icon should be chan…

chrome/browser/ui/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 CHROME_BROWSER_UI_ZOOM_ZOOM_CONTROLLER_H_
+#define CHROME_BROWSER_UI_ZOOM_ZOOM_CONTROLLER_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "chrome/browser/prefs/pref_member.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/web_contents_observer.h"
+
+class TabContentsWrapper;
+class ZoomObserver;
+
+// Per-tab class to manage the Omnibox zoom icon.
+class ZoomController : public content::NotificationObserver,
+                       public content::WebContentsObserver {
+ public:
+  enum ZoomIconState {
+    NONE = 0,
+    ZOOM_PLUS_ICON,
+    ZOOM_MINUS_ICON,
+  };
+
+  explicit ZoomController(TabContentsWrapper* tab_contents);
+  virtual ~ZoomController();
+
+  ZoomIconState zoom_icon_state() const { return zoom_icon_state_; }
+  int zoom_percent() const { return zoom_percent_; }
+
+  void set_observer(ZoomObserver* observer) { observer_ = observer; }
+
+ private:
+  // content::WebContentsObserver overrides:
+  virtual void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) OVERRIDE;
+
+  // content::NotificationObserver overrides:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  // Updates the zoom icon and zoom percentage based on current values and
+  // notifies the observer if changes have occurred.
+  void UpdateState();
+
+  // The current zoom icon state.
+  ZoomIconState zoom_icon_state_;
+
+  // The current zoom percentage.
+  int zoom_percent_;
+
+  content::NotificationRegistrar registrar_;
+
+  // Used to access the default zoom level preference.
+  DoublePrefMember default_zoom_level_;
+
+  // TabContentsWrapper that owns this instance.
+  TabContentsWrapper* tab_contents_wrapper_;
+
+  // Observer receiving notifications on state changes.
+  ZoomObserver* observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(ZoomController);
+};
+
+#endif  // CHROME_BROWSER_UI_ZOOM_ZOOM_CONTROLLER_H_