[Mac] Reimplement HoverButton and HoverImageButton using NSButton.state.

ui/base/cocoa/hover_button.mm

Index: ui/base/cocoa/hover_button.mm
diff --git a/ui/base/cocoa/hover_button.mm b/ui/base/cocoa/hover_button.mm
index a2348986560a4d0716477bcabe3e36fc80f33dab..74b6009748aaa6b3b9231ff1192fea4d8d2d1fb3 100644
--- a/ui/base/cocoa/hover_button.mm
+++ b/ui/base/cocoa/hover_button.mm
@@ -6,12 +6,11 @@
 
 @implementation HoverButton
 
-@synthesize hoverState = hoverState_;
+@synthesize isMouseInside = isMouseInside_;
 
 - (id)initWithFrame:(NSRect)frameRect {
   if ((self = [super initWithFrame:frameRect])) {
     [self setTrackingEnabled:YES];
-    hoverState_ = kHoverStateNone;
     [self updateTrackingAreas];
   }
   return self;
@@ -19,7 +18,6 @@
 
 - (void)awakeFromNib {
   [self setTrackingEnabled:YES];
-  self.hoverState = kHoverStateNone;
   [self updateTrackingAreas];
 }
 
@@ -28,31 +26,27 @@
   [super dealloc];
 }
 
+- (void)setIsMouseInside:(BOOL)isInside {
+  isMouseInside_ = isInside;
+  [self setNeedsDisplay:YES];
+}
+
+- (HoverState)hoverState {
+  if (self.state == NSOnState)
+    return kHoverStateMouseDown;
+  if (self.isMouseInside)
+    return kHoverStateMouseOver;
+  return kHoverStateNone;
+}
+
 - (void)mouseEntered:(NSEvent*)theEvent {
   if (trackingArea_.get())
-    self.hoverState = kHoverStateMouseOver;
+    self.isMouseInside = YES;
 }
 
 - (void)mouseExited:(NSEvent*)theEvent {
   if (trackingArea_.get())
-    self.hoverState = kHoverStateNone;
-}
-
-- (void)mouseDown:(NSEvent*)theEvent {
-  self.hoverState = kHoverStateMouseDown;
-  // The hover button needs to hold onto itself here for a bit.  Otherwise,
-  // it can be freed while |super mouseDown:| is in its loop, and the
-  // |checkImageState| call will crash.
-  // http://crbug.com/28220
-  scoped_nsobject<HoverButton> myself([self retain]);
-
-  [super mouseDown:theEvent];
-  // We need to check the image state after the mouseDown event loop finishes.
-  // It's possible that we won't get a mouseExited event if the button was
-  // moved under the mouse during tab resize, instead of the mouse moving over
-  // the button.
-  // http://crbug.com/31279
-  [self checkImageState];
+    self.isMouseInside = NO;
 }
 
 - (void)setTrackingEnabled:(BOOL)enabled {
@@ -96,13 +90,7 @@
   // Update the button's state if the button has moved.
   NSPoint mouseLoc = [[self window] mouseLocationOutsideOfEventStream];
   mouseLoc = [self convertPoint:mouseLoc fromView:nil];
-  self.hoverState = NSPointInRect(mouseLoc, [self bounds]) ?
-      kHoverStateMouseOver : kHoverStateNone;
-}
-
-- (void)setHoverState:(HoverState)state {
-  hoverState_ = state;
-  [self setNeedsDisplay:YES];
+  self.isMouseInside = NSPointInRect(mouseLoc, [self bounds]);
 }
 
 @end