chromeos: Fix pixelated icons in app list and launcher (part 2) (by xiyuan)

chrome/browser/extensions/extension_icon_image.cc

Index: chrome/browser/extensions/extension_icon_image.cc
diff --git a/chrome/browser/extensions/extension_icon_image.cc b/chrome/browser/extensions/extension_icon_image.cc
new file mode 100644
index 0000000000000000000000000000000000000000..dcd096815c03ab6c26653705b041539a73703acc
--- /dev/null
+++ b/chrome/browser/extensions/extension_icon_image.cc
@@ -0,0 +1,180 @@
+// 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 "chrome/browser/extensions/extension_icon_image.h"
+
+#include <vector>
+
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/extensions/extension.h"
+#include "content/public/browser/notification_service.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia_source.h"
+#include "ui/gfx/size.h"
+
+namespace {
+
+const int kMatchBiggerTreshold = 32;
+
+ExtensionResource GetExtensionIconResource(
+    const extensions::Extension* extension,
+    const ExtensionIconSet& icons,
+    int size,
+    ExtensionIconSet::MatchType match_type) {
+  std::string path = icons.Get(size, match_type);
+  if (path.empty())
+    return ExtensionResource();
+
+  return extension->GetResource(path);
+}
+
+}  // namespace
+
+namespace extensions {
+
+////////////////////////////////////////////////////////////////////////////////
+// ExtensionIconImage::Source
+
+class IconImage::Source : public gfx::ImageSkiaSource {
+ public:
+  explicit Source(IconImage* host);
+  virtual ~Source();
+
+  void ResetHost();
+
+ private:
+  // gfx::ImageSkiaSource overrides:
+  virtual gfx::ImageSkiaRep GetImageForScale(
+      ui::ScaleFactor scale_factor) OVERRIDE;
+
+  IconImage* host_;
+
+  DISALLOW_COPY_AND_ASSIGN(Source);
+};
+
+IconImage::Source::Source(IconImage* host) : host_(host) {
+}
+
+IconImage::Source::~Source() {
+}
+
+void IconImage::Source::ResetHost() {
+  host_ = NULL;
+}
+
+gfx::ImageSkiaRep IconImage::Source::GetImageForScale(
+    ui::ScaleFactor scale_factor) {
+  if (host_)
+    host_->LoadImageForScaleFactor(scale_factor);
+  return gfx::ImageSkiaRep();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ExtensionIconImage
+
+IconImage::IconImage(
+    const Extension* extension,
+    const ExtensionIconSet& icon_set,
+    int resource_size_in_dip,
+    Observer* observer)
+    : extension_(extension),
+      icon_set_(icon_set),
+      resource_size_in_dip_(resource_size_in_dip),
+      desired_size_in_dip_(resource_size_in_dip, resource_size_in_dip),
+      observer_(observer),
+      source_(NULL),
+      ALLOW_THIS_IN_INITIALIZER_LIST(tracker_(this)) {
+  source_ = new Source(this);
+  image_skia_ = gfx::ImageSkia(source_, desired_size_in_dip_);
+
+  registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
+                 content::NotificationService::AllSources());
+}
+
+IconImage::~IconImage() {
+  // |source_| could be NULL if resource does not exist.
+  if (source_)
+    source_->ResetHost();
+}
+
+void IconImage::LoadImageForScaleFactor(ui::ScaleFactor scale_factor) {
+  // Do nothing if extension is unloaded.
+  if (!extension_)
+    return;
+
+  const float scale = ui::GetScaleFactorScale(scale_factor);
+  const int resource_size_in_pixel =
+      static_cast<int>(resource_size_in_dip_ * scale);
+
+  ExtensionResource resource;
+  // We try loading bigger image only if resource size is >= 32.
+  if (resource_size_in_pixel >= kMatchBiggerTreshold) {
+    resource = GetExtensionIconResource(extension_, icon_set_,
+        resource_size_in_pixel, ExtensionIconSet::MATCH_BIGGER);
+  }
+
+  // If resource is not found by now, try matching smaller one.
+  if (resource.empty()) {
+    resource = GetExtensionIconResource(extension_, icon_set_,
+        resource_size_in_pixel, ExtensionIconSet::MATCH_SMALLER);
+  }
+
+  // If there is no resource found, bail out and notify observer of failure.
+  if (resource.empty()) {
+    if (observer_)
+      observer_->OnIconImageLoadFailed(this, scale_factor);
+    return;
+  }
+
+  int id = tracker_.next_id();
+  load_map_[id] = scale_factor;
+
+  std::vector<ImageLoadingTracker::ImageRepresentation> info_list;
+  info_list.push_back(ImageLoadingTracker::ImageRepresentation(
+      resource,
+      ImageLoadingTracker::ImageRepresentation::RESIZE_WHEN_LARGER,
+      desired_size_in_dip_.Scale(scale),
+      scale_factor));
+  tracker_.LoadImages(extension_, info_list, ImageLoadingTracker::DONT_CACHE);
+}
+
+void IconImage::OnImageLoaded(const gfx::Image& image,
+                              const std::string& extension_id,
+                              int index) {
+  LoadMap::iterator load_map_it = load_map_.find(index);
+  DCHECK(load_map_it != load_map_.end());
+
+  ui::ScaleFactor scale_factor = load_map_it->second;
+
+  load_map_.erase(load_map_it);
+
+  if (image.IsEmpty()) {
+    // There waas an error loading the image.
+    if (observer_)
+      observer_->OnIconImageLoadFailed(this, scale_factor);
+    return;
+  }
+
+  DCHECK(image.ToImageSkia()->HasRepresentation(scale_factor));
+  gfx::ImageSkiaRep rep = image.ToImageSkia()->GetRepresentation(scale_factor);
+  DCHECK(!rep.is_null());
+  image_skia_.AddRepresentation(rep);
+
+  if (observer_)
+    observer_->OnExtensionIconImageChanged(this);
+}
+
+void IconImage::Observe(int type,
+                        const content::NotificationSource& source,
+                        const content::NotificationDetails& details) {
+  DCHECK_EQ(type, chrome::NOTIFICATION_EXTENSION_UNLOADED);
+
+  const Extension* extension =
+      content::Details<extensions::UnloadedExtensionInfo>(details)->extension;
+
+  if (extension_ == extension)
+    extension_ = NULL;
+}
+
+}  // namespace extensions