Revert of Sets the default background color of inline signin and user manager to grey

extensions/components/native_app_window/native_app_window_views.cc

 // Copyright 2014 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 "extensions/components/native_app_window/native_app_window_views.h"
 
 #include "base/threading/sequenced_worker_pool.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 275 matching lines @@
     app_window_->OnNativeWindowActivated();
 }
 
 // WebContentsObserver implementation.
 
 void NativeAppWindowViews::RenderViewCreated(
     content::RenderViewHost* render_view_host) {
   if (app_window_->requested_alpha_enabled() && CanHaveAlphaEnabled()) {
     content::RenderWidgetHostView* view = render_view_host->GetView();
     DCHECK(view);
-    view->SetBackgroundColor(SK_ColorTRANSPARENT);
+    view->SetBackgroundOpaque(false);
   }
 }
 
 void NativeAppWindowViews::RenderViewHostChanged(
     content::RenderViewHost* old_host,
     content::RenderViewHost* new_host) {
   OnViewWasResized();
 }
 
 // views::View implementation.
@@ skipping 131 matching lines @@
 
 bool NativeAppWindowViews::CanHaveAlphaEnabled() const {
   return widget_->IsTranslucentWindowOpacitySupported();
 }
 
 void NativeAppWindowViews::SetVisibleOnAllWorkspaces(bool always_visible) {
   widget_->SetVisibleOnAllWorkspaces(always_visible);
 }
 
 }  // namespace native_app_window