[Mac] Adjust omnibox decoration dragging to keep image under mouse.

chrome/browser/cocoa/location_bar/bubble_decoration.h

 // Copyright (c) 2010 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_COCOA_LOCATION_BAR_BUBBLE_DECORATION_H_
 #define CHROME_BROWSER_COCOA_LOCATION_BAR_BUBBLE_DECORATION_H_
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/gtest_prod_util.h"
@@ skipping 18 matching lines @@
 
   // Implement |LocationBarDecoration|.
   virtual void DrawInFrame(NSRect frame, NSView* control_view);
   virtual CGFloat GetWidthForSpace(CGFloat width);
 
  protected:
   // Helper returning bubble width for the given |image| and |label|
   // assuming |font_| (for sizing text).  Arguments can be nil.
   CGFloat GetWidthForImageAndLabel(NSImage* image, NSString* label);
 
+  // Helper to return where the image is drawn, for subclasses to drag
+  // from.  |frame| is the decoration's frame in the containing cell.
+  NSRect GetImageRectInFrame(NSRect frame);
+
  private:
   friend class SelectedKeywordDecorationTest;
   FRIEND_TEST_ALL_PREFIXES(SelectedKeywordDecorationTest,
                            UsesPartialKeywordIfNarrow);
 
   // Contains font attribute for drawing |label_|.
   scoped_nsobject<NSDictionary> attributes_;
 
   // Image drawn in the left side of the bubble.
   scoped_nsobject<NSImage> image_;
 
   // Label to draw to right of image.  Can be |nil|.
   scoped_nsobject<NSString> label_;
 
   // Colors used to draw the bubble, should be set by the subclass
   // constructor.
   scoped_nsobject<NSColor> background_color_;
   scoped_nsobject<NSColor> border_color_;
   scoped_nsobject<NSColor> text_color_;
 
   DISALLOW_COPY_AND_ASSIGN(BubbleDecoration);
 };
 
 #endif  // CHROME_BROWSER_COCOA_LOCATION_BAR_BUBBLE_DECORATION_H_