--- a/widget/cocoa/nsChildView.mm
+++ b/widget/cocoa/nsChildView.mm
@@ -3762,22 +3762,16 @@ NSEvent* gLastDragMouseDownEvent = nil;
 }
 
 // The display system has told us that a portion of our view is dirty. Tell
 // gecko to paint it
 - (void)drawRect:(NSRect)aRect
 {
   CGContextRef cgContext = (CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
   [self drawRect:aRect inContext:cgContext];
-
-  // If we're a transparent window and our contents have changed, we need
-  // to make sure the shadow is updated to the new contents.
-  if ([[self window] isKindOfClass:[BaseWindow class]]) {
-    [(BaseWindow*)[self window] deferredInvalidateShadow];
-  }
 }
 
 - (void)drawRect:(NSRect)aRect inContext:(CGContextRef)aContext
 {
   if (!mGeckoChild || !mGeckoChild->IsVisible())
     return;
 
 #ifdef DEBUG_UPDATE

--- a/widget/cocoa/nsCocoaWindow.h
+++ b/widget/cocoa/nsCocoaWindow.h
@@ -36,19 +36,16 @@ typedef struct _nsCocoaWindowList {
 @interface BaseWindow : NSWindow
 {
   // Data Storage
   NSMutableDictionary* mState;
   BOOL mDrawsIntoWindowFrame;
   NSColor* mActiveTitlebarColor;
   NSColor* mInactiveTitlebarColor;
 
-  // Shadow
-  BOOL mScheduledShadowInvalidation;
-
   // Invalidation disabling
   BOOL mDisabledNeedsDisplay;
 
   // DPI cache. Getting the physical screen size (CGDisplayScreenSize)
   // is ridiculously slow, so we cache it in the toplevel window for all
   // descendants to use.
   float mDPI;
 
@@ -64,18 +61,16 @@ typedef struct _nsCocoaWindowList {
 
 - (void)importState:(NSDictionary*)aState;
 - (NSMutableDictionary*)exportState;
 - (void)setDrawsContentsIntoWindowFrame:(BOOL)aState;
 - (BOOL)drawsContentsIntoWindowFrame;
 - (void)setTitlebarColor:(NSColor*)aColor forActiveWindow:(BOOL)aActive;
 - (NSColor*)titlebarColorForActiveWindow:(BOOL)aActive;
 
-- (void)deferredInvalidateShadow;
-- (void)invalidateShadow;
 - (float)getDPI;
 
 - (void)mouseEntered:(NSEvent*)aEvent;
 - (void)mouseExited:(NSEvent*)aEvent;
 - (void)mouseMoved:(NSEvent*)aEvent;
 - (void)updateTrackingArea;
 - (NSView*)trackingAreaView;
 

--- a/widget/cocoa/nsCocoaWindow.mm
+++ b/widget/cocoa/nsCocoaWindow.mm
@@ -2995,17 +2995,16 @@ static NSMutableSet *gSwizzledFrameViewC
 
 - (id)initWithContentRect:(NSRect)aContentRect styleMask:(NSUInteger)aStyle backing:(NSBackingStoreType)aBufferingType defer:(BOOL)aFlag
 {
   mDrawsIntoWindowFrame = NO;
   [super initWithContentRect:aContentRect styleMask:aStyle backing:aBufferingType defer:aFlag];
   mState = nil;
   mActiveTitlebarColor = nil;
   mInactiveTitlebarColor = nil;
-  mScheduledShadowInvalidation = NO;
   mDisabledNeedsDisplay = NO;
   mDPI = GetDPI(self);
   mTrackingArea = nil;
   mDirtyRect = NSZeroRect;
   mBeingShown = NO;
   mDrawTitle = NO;
   mBrightTitlebarForeground = NO;
   mUseMenuStyle = NO;
@@ -3145,31 +3144,16 @@ static const NSString* kStateCollectionB
   }
 }
 
 - (NSColor*)titlebarColorForActiveWindow:(BOOL)aActive
 {
   return aActive ? mActiveTitlebarColor : mInactiveTitlebarColor;
 }
 
-- (void)deferredInvalidateShadow
-{
-  if (mScheduledShadowInvalidation || [self isOpaque] || ![self hasShadow])
-    return;
-
-  [self performSelector:@selector(invalidateShadow) withObject:nil afterDelay:0];
-  mScheduledShadowInvalidation = YES;
-}
-
-- (void)invalidateShadow
-{
-  [super invalidateShadow];
-  mScheduledShadowInvalidation = NO;
-}
-
 - (float)getDPI
 {
   return mDPI;
 }
 
 - (NSView*)trackingAreaView
 {
   NSView* contentView = [self contentView];