Revert 31814 - Testing to see if it caused performance problems.

Add support for observing tracking areas so that when tabs are moved underneath
our cursor, we highlight them correctly.

BUG=27458, 13208, 21448
TEST=Create a pile of tabs. 
     Select a middle one. 
     Put your cursor in some other tab. 
     Hit cmdw a couple of times
     Watch to make sure highlights occur correctly in both the tabs and the
     close buttons.

Review URL: http://codereview.chromium.org/386021

TBR=dmaclach@chromium.org
Review URL: http://codereview.chromium.org/384100

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31856 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 3 insertions, 71 deletions

diff --git a/chrome/browser/cocoa/tab_strip_controller.mm b/chrome/browser/cocoa/tab_strip_controller.mm
index 48a7747..dfc70a7 100644
--- a/chrome/browser/cocoa/tab_strip_controller.mm
+++ b/chrome/browser/cocoa/tab_strip_controller.mm
@@ -107,7 +107,6 @@ private:
 - (void)animationDidStopForController:(TabController*)controller
                              finished:(BOOL)finished;
 - (NSInteger)indexFromModelIndex:(NSInteger)index;
-- (void)mouseMoved:(NSEvent*)event;
 @end
 
 // A simple view class that prevents the Window Server from dragging the area
@@ -893,15 +892,8 @@ private:
   // tell us what to swap in in its absence.
   [tabContentsArray_ removeObjectAtIndex:index];
 
-  NSView* tab = [controller view];
-
-  // Stop observing the tab's tracking areas.
-  NSNotificationCenter* defaultCenter = [NSNotificationCenter defaultCenter];
-  [defaultCenter removeObserver:self
-                           name:NSViewDidUpdateTrackingAreasNotification
-                         object:tab];
-
   // Remove the view from the tab strip.
+  NSView* tab = [controller view];
   [tab removeFromSuperview];
 
   // Clear the tab controller's target.
@@ -1191,27 +1183,6 @@ private:
   [self layoutTabsWithAnimation:NO regenerateSubviews:NO];
 }
 
-// Called when the tracking areas for any given tab are updated. This allows
-// the individual tabs to update their hover states correctly.
-// Only generates the event if the cursor is in the tab strip.
-- (void)tabUpdateTracking:(NSNotification*)notification {
-  DCHECK([[notification object] isKindOfClass:[TabView class]]);
-  NSWindow* window = [tabView_ window];
-  NSPoint location = [window mouseLocationOutsideOfEventStream];
-  if (NSPointInRect(location, [tabView_ frame])) {
-    NSEvent* mouseEvent = [NSEvent mouseEventWithType:NSMouseMoved
-                                             location:location
-                                        modifierFlags:0
-                                            timestamp:0
-                                         windowNumber:[window windowNumber]
-                                              context:nil
-                                          eventNumber:0
-                                           clickCount:0
-                                             pressure:0];
-    [self mouseMoved:mouseEvent];
-  }
-}
-
 - (BOOL)inRapidClosureMode {
   return availableResizeWidth_ != kUseFullAvailableWidth;
 }
@@ -1281,15 +1252,6 @@ private:
 // should call |-addSubviewToPermanentList:| (or better yet, call that and then
 // |-regenerateSubviewList| to actually add it).
 - (void)regenerateSubviewList {
-  // Remove self as an observer from all the old tabs before a new set of
-  // potentially different tabs is put in place.
-  NSNotificationCenter* defaultCenter = [NSNotificationCenter defaultCenter];
-  for (NSView* view in [tabView_ subviews]) {
-    [defaultCenter removeObserver:self
-                             name:NSViewDidUpdateTrackingAreasNotification
-                           object:view];
-  }
-
   // Subviews to put in (in bottom-to-top order), beginning with the permanent
   // ones.
   NSMutableArray* subviews = [NSMutableArray arrayWithArray:permanentSubviews_];
@@ -1297,19 +1259,11 @@ private:
   NSView* selectedTabView = nil;
   // Go through tabs in reverse order, since |subviews| is bottom-to-top.
   for (TabController* tab in [tabArray_.get() reverseObjectEnumerator]) {
-    NSView* tabView = [tab view];
-
-    // Set self up to observe tabs so hover states will be correct as tabs move.
-    [defaultCenter addObserver:self
-                      selector:@selector(tabUpdateTracking:)
-                          name:NSViewDidUpdateTrackingAreasNotification
-                        object:tabView];
-
     if ([tab selected]) {
       DCHECK(!selectedTabView);
-      selectedTabView = tabView;
+      selectedTabView = [tab view];
     } else {
-      [subviews addObject:tabView];
+      [subviews addObject:[tab view]];
     }
   }
   if (selectedTabView)
diff --git a/chrome/browser/cocoa/tab_view.mm b/chrome/browser/cocoa/tab_view.mm
index 3106dd1..6ad5a05 100644
--- a/chrome/browser/cocoa/tab_view.mm
+++ b/chrome/browser/cocoa/tab_view.mm
@@ -116,28 +116,6 @@ static const NSTimeInterval kAnimationHideDuration = 0.4;
   }
 }
 
-// The tracking areas have been moved. Make sure that the close button is
-// highlighting correctly with respect to the cursor position with the new
-// tracking area locations.
-- (void)updateTrackingAreas {
-  [super updateTrackingAreas];
-
-  // Update the close buttons if the tab has moved.
-  NSPoint mouseLoc = [[self window] mouseLocationOutsideOfEventStream];
-  mouseLoc = [self convertPointFromBase:mouseLoc];
-  NSString* name = nil;
-  if (NSPointInRect(mouseLoc, [closeButton_ frame])) {
-    name = @"close_bar_h.pdf";
-  } else {
-    name = @"close_bar.pdf";
-  }
-  NSImage* newImage = nsimage_cache::ImageNamed(name);
-  NSImage* buttonImage = [closeButton_ image];
-  if (![buttonImage isEqual:newImage]) {
-    [closeButton_ setImage:newImage];
-  }
-}
-
 // Determines which view a click in our frame actually hit. It's either this
 // view or our child close button.
 - (NSView*)hitTest:(NSPoint)aPoint {