cros: Fix immersive fullscreen tabstrip revealing does not draw well

chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc

 // Copyright 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.
 
 #include "chrome/browser/ui/views/frame/immersive_mode_controller_ash.h"
 
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/wm/window_state.h"
 #include "ash/shared/immersive_revealed_lock.h"
 #include "ash/shell.h"
@@ skipping 238 matching lines @@
 
 void ImmersiveModeControllerAsh::DestroyMashRevealWidget() {
   mash_reveal_widget_.reset();
 }
 
 void ImmersiveModeControllerAsh::OnImmersiveRevealStarted() {
   DestroyMashRevealWidget();
 
   visible_fraction_ = 0;
   browser_view_->top_container()->SetPaintToLayer();
-  // In mash the window manager (ash) also renders to the non-client area. In
-  // order to see the decorations drawn by ash the layer needs to be marked as
-  // not filling bounds opaquely.
-  if (ash_util::IsRunningInMash())
-    browser_view_->top_container()->layer()->SetFillsBoundsOpaquely(false);
+  browser_view_->top_container()->layer()->SetFillsBoundsOpaquely(false);
   LayoutBrowserRootView();
   CreateMashRevealWidget();
   for (Observer& observer : observers_)
     observer.OnImmersiveRevealStarted();
 }
 
 void ImmersiveModeControllerAsh::OnImmersiveRevealEnded() {
   DestroyMashRevealWidget();
   visible_fraction_ = 0;
   browser_view_->top_container()->DestroyLayer();
@@ skipping 81 matching lines @@
                                                          const void* key,
                                                          intptr_t old) {
   // In mash the window manager may move us out of immersive mode by changing
   // the show state. When this happens notify the controller.
   DCHECK(ash_util::IsRunningInMash());
   if (key == aura::client::kShowStateKey &&
       !browser_view_->GetWidget()->IsFullscreen()) {
     SetEnabled(false);
   }
 }