[Mac] Remove a panel from stack window bounds update list when it is being removed

chrome/browser/ui/cocoa/panels/panel_stack_window_cocoa.mm

 // Copyright (c) 2013 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.
 
 #include "chrome/browser/ui/cocoa/panels/panel_stack_window_cocoa.h"
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #import "chrome/browser/ui/cocoa/panels/panel_cocoa.h"
 #import "chrome/browser/ui/cocoa/panels/panel_utils_cocoa.h"
@@ skipping 64 matching lines @@
   EnsureWindowCreated();
 
   // Make the stack window own the panel window such that all panels window
   // could be moved simulatenously when the stack window is moved.
   [window_ addChildWindow:panel->GetNativeWindow() ordered:NSWindowAbove];
 
   UpdateStackWindowBounds();
 }
 
 void PanelStackWindowCocoa::RemovePanel(Panel* panel) {
+  if (IsAnimatingPanelBounds()) {
+    // This panel is gone. We should not perform any update to it.
+    bounds_updates_.erase(panel);
+  }
+
   panels_.remove(panel);
 
   // If the native panel is closed, the native window should already be gone.
   if (!static_cast<PanelCocoa*>(panel->native_panel())->IsClosed())
     [window_ removeChildWindow:panel->GetNativeWindow()];
 
   UpdateStackWindowBounds();
 }
 
 void PanelStackWindowCocoa::MergeWith(NativePanelStackWindow* another) {
@@ skipping 276 matching lines @@
       [[NSWindow alloc] initWithContentRect:ui::kWindowSizeDeterminedLater
                                   styleMask:NSBorderlessWindowMask
                                     backing:NSBackingStoreBuffered
                                       defer:NO]);
   [window_ setBackgroundColor:[NSColor clearColor]];
   [window_ setHasShadow:YES];
   [window_ setLevel:NSNormalWindowLevel];
   [window_ orderFront:nil];
   [window_ setTitle:base::SysUTF16ToNSString(delegate_->GetTitle())];
 }