Reland "Use low resolution wallpaper for small screens"

The previous issue (http://codereview.chromium.org/10837089/) was reverted because
of win_aura compile error. It turns out that I use "small" as variable name but
"small" was defined as char when compiled on win_aura. Renamed the variable.

BUG=140336
TBR=saintlou, sky, jhawkins, lambroslambrou

Review URL: https://chromiumcodereview.appspot.com/10837110

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149977 0039d316-1c4b-4281-b951-d872f2087c98

ash/desktop_background/desktop_background_controller.cc

@@ -23,6 +23,10 @@
 
 namespace ash {
 namespace {
+
+const int kSmallWallpaperMaximalWidth = 1366;
+const int kSmallWallpaperMaximalHeight = 800;
+
 internal::RootWindowLayoutManager* GetRootWindowLayoutManager(
     aura::RootWindow* root_window) {
   return static_cast<internal::RootWindowLayoutManager*>(
@@ -32,11 +36,11 @@ internal::RootWindowLayoutManager* GetRootWindowLayoutManager(
 
 // Stores the current wallpaper data.
 struct DesktopBackgroundController::WallpaperData {
-  explicit WallpaperData(int index)
+  WallpaperData(int index, WallpaperResolution resolution)
       : wallpaper_index(index),
-        wallpaper_layout(GetWallpaperInfo(index).layout),
+        wallpaper_layout(GetWallpaperViewInfo(index, resolution).layout),
         wallpaper_image(*(ui::ResourceBundle::GetSharedInstance().GetImageNamed(
-            GetWallpaperInfo(index).id).ToImageSkia())) {
+            GetWallpaperViewInfo(index, resolution).id).ToImageSkia())) {
   }
   WallpaperData(WallpaperLayout layout, const gfx::ImageSkia& image)
       : wallpaper_index(-1),
@@ -54,7 +58,9 @@ class DesktopBackgroundController::WallpaperOperation
     : public base::RefCountedThreadSafe<
           DesktopBackgroundController::WallpaperOperation> {
  public:
-  explicit WallpaperOperation(int index) : index_(index) {
+  WallpaperOperation(int index, WallpaperResolution resolution)
+      : index_(index),
+        resolution_(resolution) {
   }
 
   static void Run(scoped_refptr<WallpaperOperation> wo) {
@@ -64,7 +70,7 @@ class DesktopBackgroundController::WallpaperOperation
   void LoadingWallpaper() {
     if (cancel_flag_.IsSet())
       return;
-    wallpaper_data_.reset(new WallpaperData(index_));
+    wallpaper_data_.reset(new WallpaperData(index_, resolution_));
   }
 
   void Cancel() {
@@ -85,7 +91,9 @@ class DesktopBackgroundController::WallpaperOperation
 
   scoped_ptr<WallpaperData> wallpaper_data_;
 
-  int index_;
+  const int index_;
+
+  const WallpaperResolution resolution_;
 
   DISALLOW_COPY_AND_ASSIGN(WallpaperOperation);
 };
@@ -123,7 +131,17 @@ void DesktopBackgroundController::OnRootWindowAdded(
   switch (desktop_background_mode_) {
     case BACKGROUND_IMAGE:
       if (current_wallpaper_.get()) {
-        SetDesktopBackgroundImage(root_window);
+        gfx::Size root_window_size = root_window->GetHostSize();
+        int wallpaper_width = current_wallpaper_->wallpaper_image.width();
+        int wallpaper_height = current_wallpaper_->wallpaper_image.height();
+        // Loads a higher resolution wallpaper if needed.
+        if ((wallpaper_width < root_window_size.width() ||
+             wallpaper_height < root_window_size.height()) &&
+            current_wallpaper_->wallpaper_index != -1 &&
+            current_wallpaper_->wallpaper_layout != TILE)
+          SetDefaultWallpaper(current_wallpaper_->wallpaper_index, true);
+        else
+          SetDesktopBackgroundImage(root_window);
       } else {
         internal::CreateDesktopBackground(root_window);
       }
@@ -134,7 +152,8 @@ void DesktopBackgroundController::OnRootWindowAdded(
   }
 }
 
-void DesktopBackgroundController::SetDefaultWallpaper(int index) {
+void DesktopBackgroundController::SetDefaultWallpaper(int index,
+                                                      bool force_reload) {
   // We should not change background when index is invalid. For instance, at
   // login screen or stub_user login.
   if (index == ash::GetInvalidWallpaperIndex()) {
@@ -145,12 +164,23 @@ void DesktopBackgroundController::SetDefaultWallpaper(int index) {
     return;
   }
 
-  if (current_wallpaper_.get() && current_wallpaper_->wallpaper_index == index)
+  if (!force_reload && current_wallpaper_.get() &&
+      current_wallpaper_->wallpaper_index == index)
     return;
 
   CancelPendingWallpaperOperation();
 
-  wallpaper_op_ = new WallpaperOperation(index);
+  WallpaperResolution resolution = SMALL;
+  Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
+  for (Shell::RootWindowList::iterator iter = root_windows.begin();
+       iter != root_windows.end(); ++iter) {
+    gfx::Size root_window_size = (*iter)->GetHostSize();
+    if (root_window_size.width() > kSmallWallpaperMaximalWidth ||
+        root_window_size.height() > kSmallWallpaperMaximalHeight)
+      resolution = LARGE;
+  }
+
+  wallpaper_op_ = new WallpaperOperation(index, resolution);
   base::WorkerPool::PostTaskAndReply(
       FROM_HERE,
       base::Bind(&WallpaperOperation::Run, wallpaper_op_),

ash/desktop_background/desktop_background_controller.h

@@ -71,8 +71,10 @@ class ASH_EXPORT DesktopBackgroundController {
   void OnRootWindowAdded(aura::RootWindow* root_window);
 
   // Loads default wallpaper at |index| asynchronously and sets to current
-  // wallpaper after loaded.
-  void SetDefaultWallpaper(int index);
+  // wallpaper after loaded. When |force_reload| is true, reload wallpaper
+  // for all root windows even if |index| is the same as current wallpaper. It
+  // must be true when a different resolution of current wallpaper is needed.
+  void SetDefaultWallpaper(int index, bool force_reload);
 
   // Sets the user selected custom wallpaper. Called when user selected a file
   // from file system or changed the layout of wallpaper.

ash/desktop_background/desktop_background_resources.h

@@ -19,10 +19,21 @@ enum WallpaperLayout {
   TILE,
 };
 
-struct ASH_EXPORT WallpaperInfo {
+enum WallpaperResolution {
+  LARGE,
+  SMALL
+};
+
+// Encapsulates wallpaper infomation needed by desktop background view.
+struct ASH_EXPORT WallpaperViewInfo {
   int id;
-  int thumb_id;
   WallpaperLayout layout;
+};
+
+struct ASH_EXPORT WallpaperInfo {
+  WallpaperViewInfo large_wallpaper;
+  WallpaperViewInfo small_wallpaper;
+  int thumb_id;
   // TODO(bshe): author member should be encoded to UTF16. We need to use i18n
   // string for this member after M19.
   const char* author;
@@ -39,6 +50,8 @@ ASH_EXPORT int GetNextWallpaperIndex(int index);
 ASH_EXPORT int GetSolidColorIndex();
 ASH_EXPORT int GetWallpaperCount();
 ASH_EXPORT const WallpaperInfo& GetWallpaperInfo(int index);
+ASH_EXPORT const WallpaperViewInfo& GetWallpaperViewInfo(int index,
+    WallpaperResolution resolution);
 
 }  // namespace ash
 

chrome/browser/chromeos/login/wallpaper_manager.cc

@@ -206,7 +206,7 @@ void WallpaperManager::InitializeWallpaper() {
         // TODO(nkostylev): Add switch to disable wallpaper transition on OOBE.
         // Should be used on test images so that they are not slowed down.
         ash::Shell::GetInstance()->desktop_background_controller()->
-            SetDefaultWallpaper(kDefaultOOBEWallpaperIndex);
+            SetDefaultWallpaper(kDefaultOOBEWallpaperIndex, false);
       } else {
         bool show_users = true;
         bool result = CrosSettings::Get()->GetBoolean(
@@ -215,7 +215,7 @@ void WallpaperManager::InitializeWallpaper() {
                        << kAccountsPrefShowUserNamesOnSignIn;
         if (!show_users) {
           ash::Shell::GetInstance()->desktop_background_controller()->
-              SetDefaultWallpaper(ash::GetSolidColorIndex());
+              SetDefaultWallpaper(ash::GetSolidColorIndex(), false);
         }
       }
     }
@@ -307,7 +307,7 @@ void WallpaperManager::SetInitialUserWallpaper(const std::string& username) {
   // crash and speed up the tests by avoid loading wallpaper.
   if (ash::Shell::HasInstance()) {
     ash::Shell::GetInstance()->desktop_background_controller()->
-        SetDefaultWallpaper(current_user_wallpaper_index_);
+        SetDefaultWallpaper(current_user_wallpaper_index_, false);
   }
 }
 
@@ -366,7 +366,7 @@ void WallpaperManager::SetUserWallpaper(const std::string& email) {
     return;
   }
   ash::Shell::GetInstance()->desktop_background_controller()->
-      SetDefaultWallpaper(index);
+      SetDefaultWallpaper(index, false);
   SetLastSelectedUser(email);
 }
 
@@ -381,7 +381,7 @@ void WallpaperManager::OnUserDeselected() {
   if (!UserManager::Get()->IsUserLoggedIn()) {
     // This will set default login wallpaper (#fefefe).
     ash::Shell::GetInstance()->desktop_background_controller()->
-        SetDefaultWallpaper(ash::GetSolidColorIndex());
+        SetDefaultWallpaper(ash::GetSolidColorIndex(), false);
   }
 }
 

chrome/browser/ui/webui/options2/chromeos/set_wallpaper_options_handler.cc

@@ -248,7 +248,7 @@ void SetWallpaperOptionsHandler::HandleDailyWallpaper(const ListValue* args) {
     index = ash::GetNextWallpaperIndex(index);
   UserManager::Get()->SaveLoggedInUserWallpaperProperties(User::DAILY, index);
   ash::Shell::GetInstance()->desktop_background_controller()->
-      SetDefaultWallpaper(index);
+      SetDefaultWallpaper(index, false);
   base::StringValue image_url(GetDefaultWallpaperThumbnailURL(index));
   base::FundamentalValue is_daily(true);
   web_ui()->CallJavascriptFunction("SetWallpaperOptions.setSelectedImage",