[Toolbar Mac UI] Simplify and correct omnibox pinning

chrome/browser/ui/cocoa/extensions/browser_actions_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/extensions/browser_actions_controller.h"
 
 #include <string>
 
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/ui/browser.h"
@@ skipping 496 matching lines @@
       // Make sure the button is within the visible container.
       if ([button superview] != containerView_) {
         // We add the subview under the sibling views so that when it
         // "slides in", it does so under its neighbors.
         [containerView_ addSubview:button
                         positioned:NSWindowBelow
                         relativeTo:nil];
       }
       // We need to set the alpha value in case the container has resized.
       [button setAlphaValue:1.0];
-    } else if ([button superview] == containerView_) {
+    } else if ([button superview] == containerView_ &&
+               ![containerView_ userIsResizing]) {
+      // If the user is resizing, all buttons are (and should be) on the
+      // container view.
       [button removeFromSuperview];
       [button setAlphaValue:0.0];
     }
   }
 }
 
 - (void)removeViewForAction:(ToolbarActionViewController*)action {
   BrowserActionButton* button = [self buttonForId:action->GetId()];
 
   [button removeFromSuperview];
@@ skipping 340 matching lines @@
 - (ToolbarActionsBar*)toolbarActionsBar {
   return toolbarActionsBar_.get();
 }
 
 + (BrowserActionsController*)fromToolbarActionsBarDelegate:
     (ToolbarActionsBarDelegate*)delegate {
   return static_cast<ToolbarActionsBarBridge*>(delegate)->controller_for_test();
 }
 
 @end