[Mac] Fix for fullscreen toolbar

chrome/browser/ui/cocoa/fullscreen_toolbar_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/fullscreen_toolbar_controller.h"
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #import "base/mac/mac_util.h"
 #include "base/mac/sdk_forward_declarations.h"
 #import "chrome/browser/ui/cocoa/browser_window_controller.h"
 #include "chrome/common/chrome_switches.h"
 #import "third_party/google_toolbox_for_mac/src/AppKit/GTMNSAnimation+Duration.h"
 #import "ui/base/cocoa/nsview_additions.h"
+#import "ui/base/cocoa/tracking_area.h"
 
 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 NSTimeInterval kDropdownAnimationDuration = 0.12;
+// The duration of the toolbar show/hide animation.
+const NSTimeInterval kDropdownAnimationDuration = 0.20;
 
-// The duration the toolbar is revealed for tab strip changes.
-const NSTimeInterval kDropdownForTabStripChangesDuration = 0.75;
+// If the fullscreen toolbar is hidden, it is difficult for the user to see
+// changes in the tabstrip. As a result, if a tab is inserted or the current
+// tab switched to a new one, the toolbar must animate in and out to display
+// the tabstrip changes to the user. The animation drops down the toolbar and
+// then wait for 0.75 seconds before it hides the toolbar.
+const NSTimeInterval kTabStripChangesDelay = 0.75;
+
+// Additional height threshold added at the toolbar's bottom. This is to mimic
+// threshold the mouse position needs to be at before the menubar automatically
+// hides.
+const CGFloat kTrackingAreaAdditionalThreshold = 24;
 
 // The event kind value for a undocumented menubar show/hide Carbon event.
 const CGFloat kMenuBarRevealEventKind = 2004;
 
 // The amount by which the floating bar is offset downwards (to avoid the menu)
 // when the toolbar is hidden. (We can't use |-[NSMenu menuBarHeight]| since it
 // returns 0 when the menu bar is hidden.)
 const CGFloat kFloatingBarVerticalOffset = 22;
 
 OSStatus MenuBarRevealHandler(EventHandlerCallRef handler,
                               EventRef event,
                               void* context) {
   FullscreenToolbarController* self =
       static_cast<FullscreenToolbarController*>(context);
 
   // If Chrome has multiple fullscreen windows in their own space, the Handler
   // becomes flaky and might start receiving kMenuBarRevealEventKind events
   // from another space. Since the menubar in the another space is in either a
   // shown or hidden state, it will give us a reveal fraction of 0.0 or 1.0.
   // As such, we should ignore the kMenuBarRevealEventKind event if it gives
   // us a fraction of 0.0 or 1.0, and rely on kEventMenuBarShown and
   // kEventMenuBarHidden to set these values.
-  if (![self isFullscreenTransitionInProgress]) {
+  if (![self isFullscreenTransitionInProgress] && [self isInFullscreen]) {
     if (GetEventKind(event) == kMenuBarRevealEventKind) {
       CGFloat revealFraction = 0;
       GetEventParameter(event, FOUR_CHAR_CODE('rvlf'), typeCGFloat, NULL,
                         sizeof(CGFloat), NULL, &revealFraction);
       if (revealFraction > 0.0 && revealFraction < 1.0)
         [self setMenuBarRevealProgress:revealFraction];
     } else if (GetEventKind(event) == kEventMenuBarShown) {
       [self setMenuBarRevealProgress:1.0];
     } else {
       [self setMenuBarRevealProgress:0.0];
@@ skipping 60 matching lines @@
   [controller_ changeToolbarFraction:fraction];
 }
 
 @end
 
 @interface FullscreenToolbarController (PrivateMethods)
 
 // Updates the visibility of the menu bar and the dock.
 - (void)updateMenuBarAndDockVisibility;
 
+// Methods to set up or remove the tracking area.
+- (void)setupTrackingArea;
+- (void)removeTrackingAreaIfNecessary;
+
+// Returns YES if the mouse is inside the tracking area.
+- (BOOL)mouseInsideTrackingArea;
+
 // Whether the current screen is expected to have a menu bar, regardless of
 // current visibility of the menu bar.
 - (BOOL)doesScreenHaveMenuBar;
 
 // Returns YES if the window is on the primary screen.
 - (BOOL)isWindowOnPrimaryScreen;
 
 // Returns |kFullScreenModeHideAll| when the overlay is hidden and
 // |kFullScreenModeHideDock| when the overlay is shown.
 - (base::mac::FullScreenMode)desiredSystemFullscreenMode;
 
 // Change the overlay to the given fraction, with or without animation. Only
 // guaranteed to work properly with |fraction == 0| or |fraction == 1|. This
 // performs the show/hide (animation) immediately. It does not touch the timers.
 - (void)changeOverlayToFraction:(CGFloat)fraction withAnimation:(BOOL)animate;
 
+// Releases the bar visibility and hides the toolbar.
+- (void)releaseAndHideBarVisibility;
+
 // Cancels the timer for hiding the floating bar.
 - (void)cancelHideTimer;
 
 // Methods called when the hide timers fire. Do not call directly.
 - (void)hideTimerFire:(NSTimer*)timer;
 
 // Stops any running animations, etc.
 - (void)cleanup;
 
 // Shows and hides the UI associated with this window being active (having main
@@ skipping 39 matching lines @@
 
   return self;
 }
 
 - (void)dealloc {
   RemoveEventHandler(menuBarTrackingHandler_);
   DCHECK(!inFullscreenMode_);
   [super dealloc];
 }
 
-- (void)setupFullscreenToolbarWithDropdown:(BOOL)showDropdown {
+- (void)setupFullscreenToolbarForContentView:(NSView*)contentView
+                                showDropdown:(BOOL)showDropdown {
   DCHECK(!inFullscreenMode_);
+  contentView_ = contentView;
+
   inFullscreenMode_ = YES;
+
   [self changeToolbarFraction:(showDropdown ? 1 : 0)];
   [self updateMenuBarAndDockVisibility];
 
   // Register for notifications.  Self is removed as an observer in |-cleanup|.
   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
   NSWindow* window = [browserController_ window];
 
   [nc addObserver:self
          selector:@selector(windowDidBecomeMain:)
              name:NSWindowDidBecomeMainNotification
@@ skipping 78 matching lines @@
     return;
   if (systemFullscreenMode_ == base::mac::kFullScreenModeNormal)
     base::mac::RequestFullScreen(mode);
   else if (mode == base::mac::kFullScreenModeNormal)
     base::mac::ReleaseFullScreen(systemFullscreenMode_);
   else
     base::mac::SwitchFullScreenModes(systemFullscreenMode_, mode);
   systemFullscreenMode_ = mode;
 }
 
+- (void)mouseEntered:(NSEvent*)event {
+  // Empty implementation. Required for CrTrackingArea.
+}
+
+- (void)mouseExited:(NSEvent*)event {
+  DCHECK(inFullscreenMode_);
+
+  // Release the toolbar if the mouse exits the tracking area,
+  if ([event trackingArea] == trackingArea_.get())
+    [self releaseAndHideBarVisibility];
+}
+
 - (void)changeToolbarFraction:(CGFloat)fraction {
-  toolbarFraction_ = fraction;
+  toolbarFraction_ =
+      [browserController_ isBarVisibilityLockedForOwner:nil] ? 1.0 : fraction;

[erikchen, 2016/08/23 21:19:58]

This line concerns me a lot. The previous method seemed very straight forward:

1. Change toolbarFraction to |fraction|.
2. Redraw.

The new method now does:

1. Change toolbarFraction to |fraction|, unless some external state has been
set, in which case set it to 1.0.
2. Redraw.

This seems like we're mixing state and layout logic again. If at some point the
state for "[browserController_ isBarVisibilityLockedForOwner:nil]" changes,
won't toolbarFraction_ have the wrong information in it?

+
   [browserController_ layoutSubviews];
 
   // In AppKit fullscreen, moving the mouse to the top of the screen toggles
   // menu visibility. Replicate the same effect for immersive fullscreen.
   if ([browserController_ isInImmersiveFullscreen])
     [self updateMenuBarAndDockVisibility];
 }
 
 // This method works, but is fragile.
 //
@@ skipping 12 matching lines @@
 
   return [self shouldShowMenubarInImmersiveFullscreen]
              ? -[self floatingBarVerticalOffset]
              : 0;
 }
 
 - (BOOL)isFullscreenTransitionInProgress {
   return [browserController_ isFullscreenTransitionInProgress];
 }
 
+- (BOOL)isInFullscreen {
+  return inFullscreenMode_;
+}
+
 - (BOOL)isMouseOnScreen {
   return NSMouseInRect([NSEvent mouseLocation],
                        [[browserController_ window] screen].frame, false);
 }
 
+- (void)setTrackingAreaFromOverlayFrame:(NSRect)frame {
+  trackingAreaFrame_ = frame;
+  trackingAreaFrame_.origin.y -= kTrackingAreaAdditionalThreshold;
+  trackingAreaFrame_.size.height += kTrackingAreaAdditionalThreshold;
+}
+
 - (void)animationDidStop:(NSAnimation*)animation {
   // Reset the |currentAnimation_| pointer now that the animation is over.
   currentAnimation_.reset();
 
   if (revealToolbarForTabStripChanges_) {
     if (toolbarFraction_ > 0.0) {
       // Set the timer to hide the toolbar.
       [hideTimer_ invalidate];
-      hideTimer_.reset([[NSTimer
-          scheduledTimerWithTimeInterval:kDropdownForTabStripChangesDuration
-                                  target:self
-                                selector:@selector(hideTimerFire:)
-                                userInfo:nil
-                                 repeats:NO] retain]);
+      hideTimer_.reset(
+          [[NSTimer scheduledTimerWithTimeInterval:kTabStripChangesDelay
+                                            target:self
+                                          selector:@selector(hideTimerFire:)
+                                          userInfo:nil
+                                           repeats:NO] retain]);
     } else {
       revealToolbarForTabStripChanges_ = NO;
     }
   }
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [self animationDidStop:animation];
+  [self setupTrackingArea];
 }
 
 - (void)setMenuBarRevealProgress:(CGFloat)progress {
   // If the menubarFraction increases, check if we are in the right screen
   // so that the toolbar is not revealed on the wrong screen.
   if (![self isMouseOnScreen] && progress > menubarFraction_)

[erikchen, 2016/08/23 21:19:58]

If the active screen changes, but the menubar fraction doesn't change, then the
|menubarFraction_| ivar will have the wrong information, and problems will
ensue, I believe? Layout logic should be kept separate from underlying state. 

     return;
 
   menubarFraction_ = progress;
 
   // If an animation is not running, then -layoutSubviews will not be called
   // for each tick of the menu bar reveal. Do that manually.
   // TODO(erikchen): The animation is janky. layoutSubviews need a refactor so
   // that it calls setFrameOffset: instead of setFrame: if the frame's size has
   // not changed.
   if (!currentAnimation_.get()) {
     if (self.slidingStyle != fullscreen_mac::OMNIBOX_TABS_NONE)
-      toolbarFraction_ = progress;
-    [browserController_ layoutSubviews];
+      [self changeToolbarFraction:progress];
+    else
+      [browserController_ layoutSubviews];
+  }
+
+  if (toolbarFraction_ == 1.0) {
+    // Lock the toolbar's visibility and set up the tracking area.
+    [browserController_ lockBarVisibilityForOwner:self withAnimation:NO];
+    [self setupTrackingArea];
+
+    // If the menubar is gone, check if the mouse is inside the new tracking
+    // area. There's a chance that the tracking area had slipped away from the
+    // cursor when toolbar shifted up from the menubar changes. As a result,
+    // this would've prevent us from getting a |mouseExited:| call.
+    if (menubarFraction_ == 0 && ![self mouseInsideTrackingArea])
+      [self releaseAndHideBarVisibility];
   }
 }
 
 @end
 
 @implementation FullscreenToolbarController (PrivateMethods)
 
 - (void)updateMenuBarAndDockVisibility {
   if (![self isMouseOnScreen] ||
       ![browserController_ isInImmersiveFullscreen]) {
     [self setSystemFullscreenModeTo:base::mac::kFullScreenModeNormal];
     return;
   }
 
   // The screen does not have a menu bar, so there's no need to hide it.
   if (![self doesScreenHaveMenuBar]) {
     [self setSystemFullscreenModeTo:base::mac::kFullScreenModeHideDock];
     return;
   }
 
   [self setSystemFullscreenModeTo:[self desiredSystemFullscreenMode]];
 }
 
+- (void)setupTrackingArea {
+  if (trackingArea_) {
+    // If the tracking rectangle is already |trackingAreaBounds_|, quit early.
+    NSRect oldRect = [trackingArea_ rect];
+    if (NSEqualRects(trackingAreaFrame_, oldRect))
+      return;
+
+    // Otherwise, remove it.
+    [self removeTrackingAreaIfNecessary];
+  }
+
+  // Create and add a new tracking area for |frame|.
+  trackingArea_.reset([[CrTrackingArea alloc]
+      initWithRect:trackingAreaFrame_
+           options:NSTrackingMouseEnteredAndExited | NSTrackingActiveInKeyWindow
+             owner:self
+          userInfo:nil]);
+  DCHECK(contentView_);
+  [contentView_ addTrackingArea:trackingArea_];
+}
+
+- (void)removeTrackingAreaIfNecessary {
+  if (trackingArea_) {
+    DCHECK(contentView_);  // |contentView_| better be valid.
+    [contentView_ removeTrackingArea:trackingArea_];
+    trackingArea_.reset();
+  }
+}
+
+- (BOOL)mouseInsideTrackingArea {
+  NSWindow* window = [browserController_ window];
+  NSPoint mouseLoc = [window mouseLocationOutsideOfEventStream];
+  NSPoint mousePos = [contentView_ convertPoint:mouseLoc fromView:nil];
+  return NSMouseInRect(mousePos, trackingAreaFrame_, [contentView_ isFlipped]);
+}
+
 - (BOOL)doesScreenHaveMenuBar {
   if (![[NSScreen class]
           respondsToSelector:@selector(screensHaveSeparateSpaces)])
     return [self isWindowOnPrimaryScreen];
 
   BOOL eachScreenShouldHaveMenuBar = [NSScreen screensHaveSeparateSpaces];
   return eachScreenShouldHaveMenuBar ?: [self isWindowOnPrimaryScreen];
 }
 
 - (BOOL)isWindowOnPrimaryScreen {
@@ skipping 28 matching lines @@
   // 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)releaseAndHideBarVisibility {
+  // There are two ways for the toolbar to hide:
+  // 1. Via the menubar, if the menubar is fully visible.
+  //    With its visibility released, the Carbon menubar events will hide the
+  //    toobar in sync with the menubar. For this case, we need to call
+  //    ensureOverlayShownWithAnimation: so that the toolbar won't hide before
+  //    the menubar does.
+  // 2. Via DropdownAnimation, if the menubar is already gone. The animation is
+  //    created when we call releaseBarVisibilityForOwner:, and it will hide
+  //    the toolbar.
+  [browserController_ releaseBarVisibilityForOwner:self withAnimation:YES];
+  if (menubarFraction_ == 1.0)
+    [self ensureOverlayShownWithAnimation:NO];
+
+  [self removeTrackingAreaIfNecessary];
+}
+
 - (void)cancelHideTimer {
   [hideTimer_ invalidate];
   hideTimer_.reset();
 }
 
 - (void)hideTimerFire:(NSTimer*)timer {
   DCHECK_EQ(hideTimer_, timer);  // This better be our hide timer.
   [hideTimer_ invalidate];       // Make sure it doesn't repeat.
   hideTimer_.reset();            // And get rid of it.
   [self changeOverlayToFraction:0 withAnimation:YES];
 }
 
 - (void)cleanup {
   [self cancelAnimationAndTimer];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
 
+  [self removeTrackingAreaIfNecessary];
+
   // This isn't tracked when not in fullscreen mode.
   [browserController_ releaseBarVisibilityForOwner:self withAnimation:NO];
 
   // Call the main status resignation code to perform the associated cleanup,
   // since we will no longer be receiving actual status resignation
   // notifications.
   [self setSystemFullscreenModeTo:base::mac::kFullScreenModeNormal];
 
   // No more calls back up to the BWC.
   browserController_ = nil;
 }
 
 - (void)showActiveWindowUI {
   [self updateMenuBarAndDockVisibility];
 }
 
 - (void)hideActiveWindowUI {
   [self updateMenuBarAndDockVisibility];
 }
 
 - (BOOL)shouldShowMenubarInImmersiveFullscreen {
   return [self doesScreenHaveMenuBar] && toolbarFraction_ > 0.99;
 }
 
 @end