If customization includes default wallpaper, download and apply it.

ash/desktop_background/desktop_background_controller.cc

Index: ash/desktop_background/desktop_background_controller.cc
diff --git a/ash/desktop_background/desktop_background_controller.cc b/ash/desktop_background/desktop_background_controller.cc
index 7673f29aa6a48d9439e9397c4663105e09f001b3..a84cb52753533564d2f2257368a4295022a37cbd 100644
--- a/ash/desktop_background/desktop_background_controller.cc
+++ b/ash/desktop_background/desktop_background_controller.cc
@@ -33,6 +33,10 @@
 #include "ui/gfx/rect.h"
 #include "ui/views/widget/widget.h"
 
+#if defined(OS_CHROMEOS)
+#include "chrome/browser/chromeos/login/wallpaper_manager.h"

[Daniel Erat, 2014/03/24 16:25:48]

ash isn't allowed to depend on chrome. you need to make the chrome code call
into this class instead. see suggestions below.

[Alexander Alekseev, 2014/03/24 17:33:43]

Done.

+#endif
+
 using ash::internal::DesktopBackgroundWidgetController;
 using content::BrowserThread;
 
@@ -160,7 +164,8 @@ DesktopBackgroundController::DesktopBackgroundController()
       desktop_background_mode_(BACKGROUND_NONE),
       current_default_wallpaper_resource_id_(-1),
       weak_ptr_factory_(this),
-      wallpaper_reload_delay_(kWallpaperReloadDelayMs) {
+      wallpaper_reload_delay_(kWallpaperReloadDelayMs),
+      customization_applied_(false) {
   Shell::GetInstance()->display_controller()->AddObserver(this);
 }
 
@@ -208,29 +213,59 @@ void DesktopBackgroundController::OnRootWindowAdded(aura::Window* root_window) {
   InstallDesktopController(root_window);
 }
 
+void DesktopBackgroundController::CheckForCustomization() {
+#if defined(OS_CHROMEOS)
+  if (customization_applied_)
+    return;
+  customization_applied_ = true;
+
+  if (chromeos::WallpaperManager::ShouldUseCustomizedDefaultWallpaper()) {
+    customized_default_wallpaper_file_small_ = chromeos::WallpaperManager::
+        GetCustomizedWallpaperDefaultRescaledSmallFileName();
+    customized_default_wallpaper_file_large_ = chromeos::WallpaperManager::
+        GetCustomizedWallpaperDefaultRescaledLargeFileName();
+    VLOG(1) << "Start with customized wallpapers: small_file_name = '"
+            << customized_default_wallpaper_file_small_.value()
+            << "', large_file_name = '"
+            << customized_default_wallpaper_file_large_.value() << "'";
+  }
+#endif
+}
+
 bool DesktopBackgroundController::SetDefaultWallpaper(bool is_guest) {
   VLOG(1) << "SetDefaultWallpaper: is_guest=" << is_guest;
   const bool use_large =
       GetAppropriateResolution() == WALLPAPER_RESOLUTION_LARGE;
-
-  base::FilePath file_path;
-  WallpaperLayout file_layout = use_large ? WALLPAPER_LAYOUT_CENTER_CROPPED :
-      WALLPAPER_LAYOUT_CENTER;
-  int resource_id = use_large ? IDR_AURA_WALLPAPER_DEFAULT_LARGE :
-      IDR_AURA_WALLPAPER_DEFAULT_SMALL;
-  WallpaperLayout resource_layout = WALLPAPER_LAYOUT_TILE;
-
   CommandLine* command_line = command_line_for_testing_ ?
       command_line_for_testing_ : CommandLine::ForCurrentProcess();
-  const char* switch_name = NULL;
+
+  CheckForCustomization();
+
+  base::FilePath file_path;
   if (is_guest) {
-    switch_name = use_large ? switches::kAshGuestWallpaperLarge :
-        switches::kAshGuestWallpaperSmall;
+    const char* switch_name = use_large ? switches::kAshGuestWallpaperLarge
+                                        : switches::kAshGuestWallpaperSmall;
+    file_path = command_line->GetSwitchValuePath(switch_name);
+  } else if (use_large && !customized_default_wallpaper_file_large_.empty()) {
+    file_path = customized_default_wallpaper_file_large_;
+  } else if (!use_large && !customized_default_wallpaper_file_small_.empty()) {
+    file_path = customized_default_wallpaper_file_small_;
   } else {
-    switch_name = use_large ? switches::kAshDefaultWallpaperLarge :
-        switches::kAshDefaultWallpaperSmall;
+    const char* switch_name = use_large ? switches::kAshDefaultWallpaperLarge
+                                        : switches::kAshDefaultWallpaperSmall;
+    file_path = command_line->GetSwitchValuePath(switch_name);
   }
-  file_path = command_line->GetSwitchValuePath(switch_name);
+  return DoSetDefaultWallpaper(file_path, use_large);
+}
+
+bool DesktopBackgroundController::DoSetDefaultWallpaper(
+    const base::FilePath& file_path,
+    const bool use_large) {
+  WallpaperLayout file_layout =
+      use_large ? WALLPAPER_LAYOUT_CENTER_CROPPED : WALLPAPER_LAYOUT_CENTER;
+  int resource_id = use_large ? IDR_AURA_WALLPAPER_DEFAULT_LARGE
+                              : IDR_AURA_WALLPAPER_DEFAULT_SMALL;
+  WallpaperLayout resource_layout = WALLPAPER_LAYOUT_TILE;
 
   if (DefaultWallpaperIsAlreadyLoadingOrLoaded(file_path, resource_id)) {
     VLOG(1) << "Default wallpaper is already loading or loaded";
@@ -251,6 +286,28 @@ bool DesktopBackgroundController::SetDefaultWallpaper(bool is_guest) {
   return true;
 }
 
+void DesktopBackgroundController::SetDefaultWallpaperPath(
+    const base::FilePath& customized_default_wallpaper_file_small,
+    const base::FilePath& customized_default_wallpaper_file_large) {
+  customization_applied_ = true;
+  const bool need_reset = DefaultWallpaperFileIsAlreadyLoadingOrLoaded(
+                              customized_default_wallpaper_file_small_) ||
+                          DefaultWallpaperFileIsAlreadyLoadingOrLoaded(
+                              customized_default_wallpaper_file_large_);

[Daniel Erat, 2014/03/24 16:25:48]

why is all this stuff necessary? does the following simpler approach work?

- add default_small_wallpaper_path_ and default_large_wallpaper_path_ members
- initialize them to the values from the flags in the c'tor
- make SetDefaultWallpaperPath() just update the members and call
SetDefaultWallpaper()
- make SetDefaultWallpaper() use the members instead of checking the switches
and leave it otherwise unchanged

[Alexander Alekseev, 2014/03/24 17:33:43]

Done.

+  customized_default_wallpaper_file_small_ =
+      customized_default_wallpaper_file_small;
+  customized_default_wallpaper_file_large_ =
+      customized_default_wallpaper_file_large;
+  if (need_reset) {
+    const bool use_large =
+        GetAppropriateResolution() == WALLPAPER_RESOLUTION_LARGE;
+    DoSetDefaultWallpaper(
+        (use_large ? customized_default_wallpaper_file_large_
+                   : customized_default_wallpaper_file_small_),
+        use_large);
+  }
+}
+
 void DesktopBackgroundController::SetCustomWallpaper(
     const gfx::ImageSkia& image,
     WallpaperLayout layout) {
@@ -340,6 +397,15 @@ bool DesktopBackgroundController::DefaultWallpaperIsAlreadyLoadingOrLoaded(
           current_default_wallpaper_resource_id_ == image_resource_id);
 }
 
+bool DesktopBackgroundController::DefaultWallpaperFileIsAlreadyLoadingOrLoaded(
+    const base::FilePath& image_file) const {

[Daniel Erat, 2014/03/24 16:25:48]

why do you need this method? it looks like it's mostly a copy-and-paste of the
existing method.

[Alexander Alekseev, 2014/03/24 17:33:43]

I need to detect the usage of default wallpaper regardless of the layout. Would
you prefer to add additional parameter to existing method
DefaultWallpaperIsAlreadyLoadingOrLoaded() to ignore resource_id?

[Daniel Erat, 2014/03/24 19:19:43]

resource_id is just a fallback that we use if we can't load the image off of the
disk, i think. i don't understand what you mean about the layout -- it looks
like it's always WALLPAPER_LAYOUT_TILE for the resource.

[Alexander Alekseev, 2014/03/24 19:52:58]

bool DesktopBackgroundController::DoSetDefaultWallpaper() :
...
  int resource_id = use_large ? IDR_AURA_WALLPAPER_DEFAULT_LARGE                

                              : IDR_AURA_WALLPAPER_DEFAULT_SMALL;  
...

Sorry, I do not know most of this code (may be resource_id check can be dropped
from existing method). I only wanted not to call
DefaultWallpaperIsAlreadyLoadingOrLoaded() twice with different resource_id . 

+  return (default_wallpaper_loader_.get() &&
+          !default_wallpaper_loader_->IsCanceled() &&
+          default_wallpaper_loader_->file_path() == image_file) ||
+         (current_wallpaper_.get() &&
+          current_default_wallpaper_path_ == image_file);
+}
+
 bool DesktopBackgroundController::CustomWallpaperIsAlreadyLoaded(
     const gfx::ImageSkia& image) const {
   return current_wallpaper_.get() &&