Fix some grammar in chrome/browser/ui/cocoa

chrome/browser/ui/cocoa/hover_button.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/hover_button.h"
 
 #import "chrome/browser/ui/cocoa/tracking_area.h"
 
 @implementation HoverButton
 
@@ skipping 23 matching lines @@
   self.hoverState = kHoverStateMouseOver;
 }
 
 - (void)mouseExited:(NSEvent*)theEvent {
   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 it's loop, and the
+  // 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
@@ skipping 43 matching lines @@
   self.hoverState = NSPointInRect(mouseLoc, [self bounds]) ?
       kHoverStateMouseOver : kHoverStateNone;
 }
 
 - (void)setHoverState:(HoverState)state {
   hoverState_ = state;
   [self setNeedsDisplay:YES];
 }
 
 @end