chromeos: Fix pixelated icons in app list and launcher (part 3)

ui/app_list/app_list_item_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 "ui/app_list/app_list_item_view.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/message_loop.h"
@@ skipping 89 matching lines @@
     if (cancel_flag_.IsSet())
       return;
 
     gfx::ImageSkia resized(gfx::ImageSkiaOperations::CreateResizedImage(image_,
         skia::ImageOperations::RESIZE_BEST, size_));
     gfx::ImageSkia shadow(
         gfx::ImageSkiaOperations::CreateImageWithDropShadow(resized, shadows_));
 
     // The following statement causes shadowed image being generated for all
     // existing image reps in |image_|. This is needed so that expensive shadow
     // generation does not run on UI thread.

[tbarzic, 2012/08/25 01:46:39]

I'm a bit concerned about this part..
I don't think we will ever do drop shadow transformation on FILE thread (we'll
get here only when we get first icon representation, which will probably be a
temp one that we use until the real one is loaded).
well, maybe not never, but that depends on a race between this operation and
image loading :)

[xiyuan, 2012/08/28 17:31:21]

As we have discussed, the icon cache is keyed by the actual pixels of the image.
So when the real icon is loaded, it has a different key compared with the
default image and we will schedule another job to run this code to generate
shadow for the real icon.

     gfx::ImageSkia::ImageSkiaReps image_reps = image_.image_reps();
     for (gfx::ImageSkia::ImageSkiaReps::const_iterator it = image_reps.begin();
          it != image_reps.end(); ++it) {
       shadow.GetRepresentation(it->scale_factor());
     }
     image_ = shadow;
   }
 
   void Cancel() {
     cancel_flag_.Set();
@@ skipping 56 matching lines @@
 
   icon_size_ = size;
   UpdateIcon();
 }
 
 void AppListItemView::UpdateIcon() {
   // Skip if |icon_size_| has not been determined.
   if (icon_size_.IsEmpty())
     return;
 
-  gfx::ImageSkia icon = model_->icon();
-  // Clear icon and bail out if model icon is empty.
-  if (icon.isNull()) {
-    icon_->SetImage(NULL);
+  const gfx::ImageSkia& icon = model_->icon();
+  // Use empty model icon and bail out. OnPaint should trigger image
+  // representation fetching and if there is an icon, UpdateIcon should be
+  // called again with the updated image.
+  if (icon.isNull() || icon.image_reps().size() == 0) {
+    icon_->SetImage(icon);
     return;
   }
 
   CancelPendingIconOperation();
 
   gfx::ImageSkia shadow;
   if (IconCache::GetInstance()->Get(icon, icon_size_, &shadow)) {
     icon_->SetImage(shadow);
   } else {
     // Schedule resize and shadow generation.
@@ skipping 107 matching lines @@
     apps_grid_view_->SetSelectedItem(this);
     title_->SetEnabledColor(kTitleHoverColor);
   } else {
     apps_grid_view_->ClearSelectedItem(this);
     model_->SetHighlighted(false);
     title_->SetEnabledColor(kTitleColor);
   }
 }
 
 }  // namespace app_list