mac: Pixel-based click detection for the tab close button

chrome/browser/ui/cocoa/hover_close_button.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/hover_close_button.h"
 
 #include "base/memory/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #import "chrome/browser/ui/cocoa/animation_utils.h"
 #include "grit/generated_resources.h"
@@ skipping 61 matching lines @@
   DCHECK(animation == fadeOutAnimation_);
   [fadeOutAnimation_ setDelegate:nil];
   [fadeOutAnimation_ release];
   fadeOutAnimation_ = nil;
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [self animationDidStop:animation];
 }
 
+// Override to only accept clicks within the bounds of the defined path, not
+// the entire bounding box. |aPoint| is in the superview's coordinate system.
+- (NSView*)hitTest:(NSPoint)point {
+  NSPoint localPoint = [self convertPoint:point fromView:[self superview]];
+  NSRect pointRect = NSMakeRect(localPoint.x, localPoint.y, 1, 1);
+
+  NSImage* hoverImage = [self imageForHoverState:kHoverStateMouseOver];
+  if ([hoverImage hitTestRect:pointRect
+      withImageDestinationRect:[self bounds]
+                       context:nil
+                         hints:nil
+                       flipped:YES])
+    return [super hitTest:point];
+  return nil;
+}
+
 - (void)drawRect:(NSRect)dirtyRect {
   NSImage* image = [self imageForHoverState:[self hoverState]];
 
   // Close boxes align left horizontally, and align center vertically.
   // http:crbug.com/14739 requires this.
   NSRect imageRect = NSZeroRect;
   imageRect.size = [image size];
 
   NSRect destRect = [self bounds];
   destRect.origin.y = floor((NSHeight(destRect) / 2)
@@ skipping 137 matching lines @@
       break;
     case kHoverStateMouseDown:
       imageID = IDR_WEB_UI_CLOSE_PRESSED;
       break;
   }
   ui::ResourceBundle& bundle = ui::ResourceBundle::GetSharedInstance();
   return bundle.GetNativeImageNamed(imageID).ToNSImage();
 }
 
 @end