Enable user change background image in settings page in Aura build.

ash/desktop_background/desktop_background_view.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_view.h"
+#include "ash/desktop_background/desktop_background_controller.h"

[flackr, 2012/03/05 16:16:03]

This include goes below with the others. desktop_background_view.h goes up here
because that is the header for this .cc file.

[bshe, 2012/03/06 01:33:27]

Done.

 
 #include <limits>
 
 #include "ash/ash_export.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "base/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
+

[flackr, 2012/03/05 16:16:03]

nit: no newline here.

[bshe, 2012/03/06 01:33:27]

Done.

 namespace internal {
-
 // For our scaling ratios we need to round positive numbers.
 static int RoundPositive(double x) {
   return static_cast<int>(floor(x + 0.5));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopBackgroundView, public:
 
 DesktopBackgroundView::DesktopBackgroundView() {
   wallpaper_ = *ui::ResourceBundle::GetSharedInstance().GetImageNamed(
       IDR_AURA_WALLPAPER_1).ToSkBitmap();

[flackr, 2012/03/05 16:16:03]

If the user has a custom background set this will have to load the default
wallpaper and then change it. I think that you should pass the wallpaper to use
in the constructor for DesktopBackgroundView and then ash::Shell or the
DesktopBackgroundController can create this view with the appropriate wallpaper.

[bshe, 2012/03/06 01:33:27]

It seems this is constructed before NOTIFICATION_LOGIN_USER_CHANGED
notification. I assume the custom background will only available after
NOTIFICATION_LOGIN_USER_CHANGED notification(I could probably be wrong). If this
is the case, unless we delay the construction of this class after
NOTIFICATION_LOGIN_USER_CHANGED, we can't initialize it with user custom
background. I have tested delay the creation of DesktopBackgroundView after we
observer the notification. But there seems to be a check failed in debug build.
(FATAL:login_performer.cc(226)] Check failed: false.) 
I am thinking we can probably do nothing in the constructor at first and set the
wallpaper after user login as a walkaround.

[flackr, 2012/03/06 17:16:49]

It makes sense that this is constructed before the shell launches, the default
background it refers to should be standardized rather than having one default
listed here, and another in the user manager. If you make the other changes I'm
suggesting, you can refer to UserManager's default background to set the
background view.

[bshe, 2012/03/06 19:56:15]

I am wondering is it also fine to dont set a specific wallpaper here(empty
constructor). And delay it after LOGIN_USER_CHANGED notification, and set the
wallpaper_ to user specific wallpaper through SetWallpaper function. This way,
there is only one standardized image as well and user dont have to load the
default wallpaper and then change it. 

I am not sure if wallpaper_ is used anywhere before the LOGIN_USER_CHANGED
notification though. On linux desktop build, it seems work fine for me.

   wallpaper_.buildMipMap(false);
 }
 
 DesktopBackgroundView::~DesktopBackgroundView() {
 }
 
+void DesktopBackgroundView::SetWallpaper(const SkBitmap& wallpaper) {
+  wallpaper_ = wallpaper;
+  wallpaper_.buildMipMap(false);
+  SchedulePaint();
+}
+
+//static
+DesktopBackgroundView* DesktopBackgroundView::GetInstance() {
+  return Singleton<DesktopBackgroundView>::get();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // DesktopBackgroundView, views::View overrides:
 
 void DesktopBackgroundView::OnPaint(gfx::Canvas* canvas) {
   // Scale the image while maintaining the aspect ratio, cropping as
   // necessary to fill the background. Ideally the image should be larger
   // than the largest display supported, if not we will center it rather than
   // streching to avoid upsampling artifacts (Note that we could tile too, but
   // decided not to do this at the moment).
   gfx::Rect wallpaper_rect(0, 0, wallpaper_.width(), wallpaper_.height());
@@ skipping 35 matching lines @@
 
 void DesktopBackgroundView::OnMouseReleased(const views::MouseEvent& event) {
   if (event.IsRightMouseButton())
     Shell::GetInstance()->ShowBackgroundMenu(GetWidget(), event.location());
 }
 
 views::Widget* CreateDesktopBackground() {
   views::Widget* desktop_widget = new views::Widget;
   views::Widget::InitParams params(
       views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
-  DesktopBackgroundView* view = new DesktopBackgroundView;
+  DesktopBackgroundView* view = DesktopBackgroundView::GetInstance();
   params.delegate = view;
   params.parent =
       Shell::GetInstance()->GetContainer(
           ash::internal::kShellWindowId_DesktopBackgroundContainer);
   desktop_widget->Init(params);
   desktop_widget->SetContentsView(view);
   desktop_widget->Show();
   desktop_widget->GetNativeView()->SetName("DesktopBackgroundView");
   return desktop_widget;
 }
 
 }  // namespace internal
 }  // namespace ash