Use a #fefefe solid color wallpaper background before user login for GAIA login flow

ash/desktop_background/desktop_background_controller.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 "ash/desktop_background/desktop_background_controller.h"
 
 #include "ash/desktop_background/desktop_background_view.h"
 #include "ash/shell.h"
 #include "ash/shell_factory.h"
 #include "ash/shell_window_ids.h"
@@ skipping 86 matching lines @@
 DesktopBackgroundController::~DesktopBackgroundController() {
   CancelPendingWallpaperOperation();
 }
 
 void DesktopBackgroundController::SetDefaultWallpaper(int index) {
   // We should not change background when index is invalid. For instance, at
   // login screen or stub_user login.
   if (index == ash::GetInvalidWallpaperIndex()) {
     CreateEmptyWallpaper();
     return;
+  } else if (index == ash::GetSolidColorIndex()) {
+    SetDesktopBackgroundSolidColorMode(SK_ColorWallpaperLogin);
+    return;
   }
 
   if (previous_index_ == index)
     return;
 
   CancelPendingWallpaperOperation();
 
   wallpaper_op_ = new WallpaperOperation(index);
   base::WorkerPool::PostTaskAndReply(
       FROM_HERE,
@@ skipping 14 matching lines @@
 
 void DesktopBackgroundController::CancelPendingWallpaperOperation() {
   // Set canceled flag of previous request to skip unneeded loading.
   if (wallpaper_op_.get())
     wallpaper_op_->Cancel();
 
   // Cancel reply callback for previous request.
   weak_ptr_factory_.InvalidateWeakPtrs();
 }
 
-void DesktopBackgroundController::SetDesktopBackgroundSolidColorMode() {
+void DesktopBackgroundController::SetDesktopBackgroundSolidColorMode(
+    SkColor color) {
   // Set a solid black background.
   // TODO(derat): Remove this in favor of having the compositor only clear the
   // viewport when there are regions not covered by a layer:
   // http://crbug.com/113445
   ui::Layer* background_layer = new ui::Layer(ui::LAYER_SOLID_COLOR);
-  background_layer->SetColor(SK_ColorBLACK);
+  background_layer->SetColor(color);
   root_window_->GetChildById(
       internal::kShellWindowId_DesktopBackgroundContainer)->
       layer()->Add(background_layer);
   GetRootWindowLayoutManager(root_window_)->SetBackgroundLayer(
       background_layer);
   GetRootWindowLayoutManager(root_window_)->SetBackgroundWidget(NULL);
   desktop_background_mode_ = BACKGROUND_SOLID_COLOR;
 }
 
 void DesktopBackgroundController::SetDesktopBackgroundImageMode(
@@ skipping 15 matching lines @@
   wallpaper_op_ = NULL;
 }
 
 void DesktopBackgroundController::CreateEmptyWallpaper() {
   gfx::ImageSkia dummy;
   internal::CreateDesktopBackground(dummy, CENTER, root_window_);
   desktop_background_mode_ = BACKGROUND_IMAGE;
 }
 
 }  // namespace ash