Move HoverButton and HoverImageButton from chrome/browser/ui/cocoa/ to ui/base/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"
-
-@implementation HoverButton
-
-@synthesize hoverState = hoverState_;
-
-- (id)initWithFrame:(NSRect)frameRect {
-  if ((self = [super initWithFrame:frameRect])) {
-    [self setTrackingEnabled:YES];
-    hoverState_ = kHoverStateNone;
-    [self updateTrackingAreas];
-  }
-  return self;
-}
-
-- (void)awakeFromNib {
-  [self setTrackingEnabled:YES];
-  self.hoverState = kHoverStateNone;
-  [self updateTrackingAreas];
-}
-
-- (void)dealloc {
-  [self setTrackingEnabled:NO];
-  [super dealloc];
-}
-
-- (void)mouseEntered:(NSEvent*)theEvent {
-  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 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];
-}
-
-- (void)setTrackingEnabled:(BOOL)enabled {
-  if (enabled) {
-    trackingArea_.reset(
-        [[CrTrackingArea alloc] initWithRect:NSZeroRect
-                                     options:NSTrackingMouseEnteredAndExited |
-                                             NSTrackingActiveAlways |
-                                             NSTrackingInVisibleRect
-                                       owner:self
-                                    userInfo:nil]);
-    [self addTrackingArea:trackingArea_.get()];
-
-    // If you have a separate window that overlaps the close button, and you
-    // move the mouse directly over the close button without entering another
-    // part of the tab strip, we don't get any mouseEntered event since the
-    // tracking area was disabled when we entered.
-    // Done with a delay of 0 because sometimes an event appears to be missed
-    // between the activation of the tracking area and the call to
-    // checkImageState resulting in the button state being incorrect.
-    [self performSelector:@selector(checkImageState)
-               withObject:nil
-               afterDelay:0];
-  } else {
-    if (trackingArea_.get()) {
-      [self removeTrackingArea:trackingArea_.get()];
-      trackingArea_.reset(nil);
-    }
-  }
-}
-
-- (void)updateTrackingAreas {
-  [super updateTrackingAreas];
-  [self checkImageState];
-}
-
-- (void)checkImageState {
-  if (!trackingArea_.get())
-    return;
-
-  // 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];
-}
-
-@end