[Mac] Use private, undocumented Carbon events to make the presentation mode animation better.

chrome/browser/ui/cocoa/presentation_mode_controller.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/presentation_mode_controller.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #import "base/mac/mac_util.h"
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #include "chrome/common/chrome_switches.h"
 #import "third_party/GTM/AppKit/GTMNSAnimation+Duration.h"
 
 NSString* const kWillEnterFullscreenNotification =
     @"WillEnterFullscreenNotification";
 NSString* const kWillLeaveFullscreenNotification =
     @"WillLeaveFullscreenNotification";
 
 namespace {
+
 // The activation zone for the main menu is 4 pixels high; if we make it any
 // smaller, then the menu can be made to appear without the bar sliding down.
 const CGFloat kDropdownActivationZoneHeight = 4;
 const NSTimeInterval kDropdownAnimationDuration = 0.12;
 const NSTimeInterval kMouseExitCheckDelay = 0.1;
 // This show delay attempts to match the delay for the main menu.
 const NSTimeInterval kDropdownShowDelay = 0.3;
 const NSTimeInterval kDropdownHideDelay = 0.2;
 
 // The amount by which the floating bar is offset downwards (to avoid the menu)
 // in presentation mode. (We can't use |-[NSMenu menuBarHeight]| since it
 // returns 0 when the menu bar is hidden.)
 const CGFloat kFloatingBarVerticalOffset = 22;
 
-}  // end namespace
+OSStatus MenuBarRevealHandler(EventHandlerCallRef handler,
+                              EventRef event,
+                              void* context) {
+  PresentationModeController* self =
+      static_cast<PresentationModeController*>(context);
+  CGFloat reveal = 0;
+  GetEventParameter(event, FOUR_CHAR_CODE('rvlf'), typeCGFloat, NULL,
+      sizeof(CGFloat), NULL, &reveal);
+  if ([self inPresentationMode])
+    [self changeFloatingBarShownFraction:reveal];
+  return CallNextEventHandler(handler, event);
+}
+
+}  // namespace
 
 
 // Helper class to manage animations for the dropdown bar.  Calls
 // [PresentationModeController changeFloatingBarShownFraction] once per
 // animation step.
 @interface DropdownAnimation : NSAnimation {
  @private
   PresentationModeController* controller_;
   CGFloat startFraction_;
   CGFloat endFraction_;
@@ skipping 116 matching lines @@
 
 
 @implementation PresentationModeController
 
 @synthesize inPresentationMode = inPresentationMode_;
 
 - (id)initWithBrowserController:(BrowserWindowController*)controller {
   if ((self = [super init])) {
     browserController_ = controller;
     systemFullscreenMode_ = base::mac::kFullScreenModeNormal;
+
+    EventTypeSpec eventSpec = { kEventClassMenu, 2004 };
+    InstallApplicationEventHandler(NewEventHandlerUPP(&MenuBarRevealHandler),
+                                   1, &eventSpec,
+                                   self, &menuBarTrackingHandler_);
   }
 
   // Let the world know what we're up to.
   [[NSNotificationCenter defaultCenter]
     postNotificationName:kWillEnterFullscreenNotification
                   object:nil];
 
   return self;
 }
 
 - (void)dealloc {
+  RemoveEventHandler(menuBarTrackingHandler_);
+  menuBarTrackingHandler_ = NULL;
+
   DCHECK(!inPresentationMode_);
   DCHECK(!trackingArea_);
   [super dealloc];
 }
 
 - (void)enterPresentationModeForContentView:(NSView*)contentView
                                showDropdown:(BOOL)showDropdown {
   DCHECK(!inPresentationMode_);
   enteringPresentationMode_ = YES;
   inPresentationMode_ = YES;
@@ skipping 255 matching lines @@
 
   // In all other cases, we want to cancel any running animation (which may be
   // to show or to hide).
   [currentAnimation_ stopAnimation];
 
   // Now, if it happens to already be in the right state, there's nothing more
   // to do.
   if ([browserController_ floatingBarShownFraction] == fraction)
     return;
 
+/*
   // Create the animation and set it up.
   currentAnimation_.reset(
       [[DropdownAnimation alloc] initWithFraction:fraction
                                      fullDuration:kDropdownAnimationDuration
                                    animationCurve:NSAnimationEaseOut
                                        controller:self]);
   DCHECK(currentAnimation_);
   [currentAnimation_ setAnimationBlockingMode:NSAnimationNonblocking];
   [currentAnimation_ setDelegate:self];
 
   // If there is an existing tracking area, remove it. We do not track mouse
   // movements during animations (see class comment in the header file).
   [self removeTrackingAreaIfNecessary];
 
   [currentAnimation_ startAnimation];
+  */
 }
 
 - (void)scheduleShowForMouse {
   [browserController_ lockBarVisibilityForOwner:self
                                   withAnimation:YES
                                           delay:YES];
 }
 
 - (void)scheduleHideForMouse {
   [browserController_ releaseBarVisibilityForOwner:self
@@ skipping 162 matching lines @@
 - (void)hideActiveWindowUI {
   if (systemFullscreenMode_ != base::mac::kFullScreenModeNormal) {
     base::mac::ReleaseFullScreen(systemFullscreenMode_);
     systemFullscreenMode_ = base::mac::kFullScreenModeNormal;
   }
 
   // TODO(rohitrao): Remove the Exit Fullscreen button.  http://crbug.com/35956
 }
 
 @end