Fix first time switching from classic to GTK theme.

ui/views/widget/widget.cc

 // 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.
 
 #include "ui/views/widget/widget.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 338 matching lines @@
   ownership_ = params.ownership;
   native_widget_ = CreateNativeWidget(params.native_widget, this)->
                    AsNativeWidgetPrivate();
   root_view_.reset(CreateRootView());
   default_theme_provider_.reset(new ui::DefaultThemeProvider);
   if (params.type == InitParams::TYPE_MENU) {
     is_mouse_button_pressed_ =
         internal::NativeWidgetPrivate::IsMouseButtonDown();
   }
   native_widget_->InitNativeWidget(params);
-  observer_manager_.Add(GetNativeTheme());
   if (RequiresNonClientView(params.type)) {
     non_client_view_ = new NonClientView;
     non_client_view_->SetFrameView(CreateNonClientFrameView());
     // Create the ClientView, add it to the NonClientView and add the
     // NonClientView to the RootView. This will cause everything to be parented.
     non_client_view_->set_client_view(widget_delegate_->CreateClientView(this));
     non_client_view_->SetOverlayView(widget_delegate_->CreateOverlayView());
     SetContentsView(non_client_view_);
     // Initialize the window's title before setting the window's initial bounds;
     // the frame view's preferred height may depend on the presence of a title.
     UpdateWindowTitle();
     non_client_view_->ResetWindowControls();
     SetInitialBounds(params.bounds);
     if (params.show_state == ui::SHOW_STATE_MAXIMIZED)
       Maximize();
     else if (params.show_state == ui::SHOW_STATE_MINIMIZED)
       Minimize();
   } else if (params.delegate) {
     SetContentsView(params.delegate->GetContentsView());
     SetInitialBoundsForFramelessWindow(params.bounds);
   }
+  // This must come after SetContentsView(). See http://crbug.com/375545

[sky, 2014/06/18 03:24:09]

Document why, I shouldn't have to chase down a bug to figure that out. In other
words, the comment should stand on its own.

+  observer_manager_.Add(GetNativeTheme());
   native_widget_initialized_ = true;
 }
 
 // Unconverted methods (see header) --------------------------------------------
 
 gfx::NativeView Widget::GetNativeView() const {
   return native_widget_->GetNativeView();
 }
 
 gfx::NativeWindow Widget::GetNativeWindow() const {
@@ skipping 1113 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // internal::NativeWidgetPrivate, NativeWidget implementation:
 
 internal::NativeWidgetPrivate* NativeWidgetPrivate::AsNativeWidgetPrivate() {
   return this;
 }
 
 }  // namespace internal
 }  // namespace views