[Cocoa] Tab audio mute control, behind a switch (off by default).

chrome/browser/ui/cocoa/tabs/media_indicator_button.h

 // Copyright 2013 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_UI_COCOA_TABS_MEDIA_INDICATOR_VIEW_H_
-#define CHROME_BROWSER_UI_COCOA_TABS_MEDIA_INDICATOR_VIEW_H_
+#ifndef CHROME_BROWSER_UI_COCOA_TABS_MEDIA_INDICATOR_BUTTON_H_
+#define CHROME_BROWSER_UI_COCOA_TABS_MEDIA_INDICATOR_BUTTON_H_
 
-#import <Cocoa/Cocoa.h>
-
+#import "base/mac/scoped_nsobject.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/tabs/tab_utils.h"
-
-class MediaIndicatorViewAnimationDelegate;
+#import "ui/base/cocoa/hover_button.h"
 
 namespace gfx {
 class Animation;
+class AnimationDelegate;
 }  // namespace gfx
 
-@interface MediaIndicatorView : NSImageView {
+// This is an HoverButton subclass that serves as both the media indicator icon
+// (audio, tab capture, etc.), and as a mute button.  It is meant to only be
+// used as a subview of TabView.
+//
+// When the indicator is transitioned to the audio playing or muting state, the
+// button functionality is enabled and begins handling mouse events.  Otherwise,
+// this view behaves like an image and all mouse events will be handled by the
+// its superview.
+//
+// Note: Send the |-setClickTarget:withAction:| message instead of the
+// |-setTarget:| and |-setAction:| messages to be notified of button clicks.
+@interface MediaIndicatorButton : HoverButton {
  @private
+  class FadeAnimationDelegate;
+
+  // Current TabMediaState.  When animating fade-in/out, this reflects the
+  // indicator state at the end of the animation.
   TabMediaState mediaState_;
-  scoped_ptr<MediaIndicatorViewAnimationDelegate> delegate_;
-  scoped_ptr<gfx::Animation> animation_;
-  TabMediaState animatingMediaState_;
+
+  // Media indicator fade-in/out animation (i.e., only on show/hide, not a
+  // continuous animation).
+  scoped_ptr<gfx::AnimationDelegate> fadeAnimationDelegate_;
+  scoped_ptr<gfx::Animation> fadeAnimation_;
+  TabMediaState showingMediaState_;
+
+  // Target and action invoked whenever a fade-in/out animation completes.  This
+  // is used by TabController to layout the TabView after an indicator has
+  // completely faded out.
+  __weak id animationDoneTarget_;
+  SEL animationDoneAction_;
+
+  // The image to show when the mouse hovers over the button.
+  base::scoped_nsobject<NSImage> affordanceImage_;
+
+  // Target and action invoked whenever an enabled button is clicked.
+  __weak id clickTarget_;
+  SEL clickAction_;
 }
 
-@property(readonly, nonatomic) TabMediaState mediaState;
-@property(readonly, nonatomic) TabMediaState animatingMediaState;
+@property(readonly, nonatomic) TabMediaState showingMediaState;
 
-// Initialize a new MediaIndicatorView in TAB_MEDIA_STATE_NONE (i.e., a
+// Initialize a new MediaIndicatorButton in TAB_MEDIA_STATE_NONE (i.e., a
 // non-active indicator).
 - (id)init;
 
-// Starts the animation to transition the indicator to the new |mediaState|.
-- (void)updateIndicator:(TabMediaState)mediaState;
+// Updates button images, starts fade animations, and activates/deactivates
+// button functionality as appropriate.
+- (void)transitionToMediaState:(TabMediaState)nextState;
 
-// Register a callback to be invoked whenever the animation completes.
-- (void)setAnimationDoneCallbackObject:(id)anObject withSelector:(SEL)selector;
+// Register a message be sent to |target| whenever fade animations complete.  A
+// weak reference on |target| is held.
+- (void)setAnimationDoneTarget:(id)target withAction:(SEL)action;
+
+// Request a message be sent to |target| whenever the enabled button has been
+// clicked.  A weak reference on |target| is held.
+- (void)setClickTarget:(id)target withAction:(SEL)action;
 
 @end
 
-@interface MediaIndicatorView(TestingAPI)
-// Turns off animations for logic testing.
-- (void)disableAnimations;
-@end
-
-#endif  // CHROME_BROWSER_UI_COCOA_TABS_MEDIA_INDICATOR_VIEW_H_
+#endif  // CHROME_BROWSER_UI_COCOA_TABS_MEDIA_INDICATOR_BUTTON_H_