Implements the "Set to default" button on the zoom bubble.

chrome/browser/ui/views/location_bar/zoom_view.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_VIEWS_LOCATION_BAR_ZOOM_VIEW_H_
 #define CHROME_BROWSER_UI_VIEWS_LOCATION_BAR_ZOOM_VIEW_H_
 
 #include "base/basictypes.h"
 #include "chrome/browser/ui/toolbar/toolbar_model.h"
+#include "chrome/browser/ui/views/location_bar/location_bar_view.h"
 #include "chrome/browser/ui/zoom/zoom_controller.h"
 #include "ui/views/controls/image_view.h"
 
 namespace views {
 class KeyEvent;
 class MouseEvent;
 }
 
 // View for the zoom icon in the Omnibox.
 class ZoomView : public views::ImageView {
  public:
-  explicit ZoomView(ToolbarModel* toolbar_model);
+  // Constructor for ZoomView. Clicking on the ZoomView shows a ZoomBubbleView,
+  // which requires the current TabContents. Because the current TabContents
+  // changes as the user switches tabs, it cannot be provided in the
+  // constructor.  Instead, a LocationBarView::Delegate is passed here so that
+  // it can be queried for the current TabContents as needed.
+  ZoomView(ToolbarModel* toolbar_model,
+           LocationBarView::Delegate* location_bar_delegate);
   virtual ~ZoomView();
 
   void SetZoomIconState(ZoomController::ZoomIconState zoom_icon_state);
   void SetZoomIconTooltipPercent(int zoom_percent);
 
   // Updates the image and its tooltip appropriately, hiding or showing the icon
   // as needed.
   void Update();
 
  private:
   // views::ImageView:
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
   virtual bool GetTooltipText(const gfx::Point& p,
                               string16* tooltip) const OVERRIDE;
   virtual bool OnMousePressed(const views::MouseEvent& event) OVERRIDE;
   virtual void OnMouseReleased(const views::MouseEvent& event) OVERRIDE;
   virtual bool OnKeyPressed(const views::KeyEvent& event) OVERRIDE;
 
   // Toolbar model used to test whether location bar input is in progress.
   ToolbarModel* toolbar_model_;
 
+  // The delegate used to get the currently visible TabContents.
+  LocationBarView::Delegate* location_bar_delegate_;
+
   // The current icon state.
   ZoomController::ZoomIconState zoom_icon_state_;
 
   // The current zoom percentage.
   int zoom_percent_;
 
   DISALLOW_COPY_AND_ASSIGN(ZoomView);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_LOCATION_BAR_ZOOM_VIEW_H_