Extremely slow scrolling on OS X with CSS "overflow: auto" and large HTML page. b=428070 r=josh sr=roc a=beltzner.

widget/src/cocoa/nsChildView.h

@@ -129,9 +129,6 @@ enum {
   // the link back to it must be weak.
   nsChildView* mGeckoChild;
     
-  // tag for our mouse enter/exit tracking rect
-  NSTrackingRectTag mMouseEnterExitTag;
-
   // Whether we're a plugin view.
   BOOL mIsPluginView;
 

widget/src/cocoa/nsChildView.mm

@@ -2746,26 +2746,6 @@ NSEvent* gLastDragEvent = nil;
 }
 
 
-// Override in order to keep our mouse enter/exit tracking rect in sync with
-// the frame of the view
-- (void)setFrame:(NSRect)frameRect
-{
-  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
-
-  [super setFrame:frameRect];
-  if (mMouseEnterExitTag)
-    [self removeTrackingRect:mMouseEnterExitTag];
-
-  if ([self window])
-    mMouseEnterExitTag = [self addTrackingRect:[self bounds]
-                                         owner:self
-                                      userData:nil
-                                  assumeInside:[[self window] acceptsMouseMovedEvents]];
-
-  NS_OBJC_END_TRY_ABORT_BLOCK;
-}
-
-
 // Make the origin of this view the topLeft corner (gecko origin) rather
 // than the bottomLeft corner (standard cocoa origin).
 - (BOOL)isFlipped
@@ -2851,34 +2831,6 @@ NSEvent* gLastDragEvent = nil;
 }
 
 
-- (void)viewWillMoveToWindow:(NSWindow *)newWindow
-{
-  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
-
-  if (mMouseEnterExitTag)
-    [self removeTrackingRect:mMouseEnterExitTag];
-
-  [super viewWillMoveToWindow:newWindow];
-
-  NS_OBJC_END_TRY_ABORT_BLOCK;
-}
-
-
-- (void)viewDidMoveToWindow
-{
-  NS_OBJC_BEGIN_TRY_ABORT_BLOCK;
-
-  if ([self window])
-    mMouseEnterExitTag = [self addTrackingRect:[self bounds] owner:self
-                                      userData:nil assumeInside: [[self window]
-                                      acceptsMouseMovedEvents]];
-
-  [super viewDidMoveToWindow];
-
-  NS_OBJC_END_TRY_ABORT_BLOCK;
-}
-
-
 - (void)viewWillStartLiveResize
 {
   NS_OBJC_BEGIN_TRY_ABORT_BLOCK;