Change browser/page action default icon defined in manifest to support hidpi.

chrome/browser/extensions/extension_action_icon_factory.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 "chrome/browser/extensions/extension_action_icon_factory.h"
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/extensions/extension_icon_image.h"
+#include "chrome/common/extensions/extension.h"
+#include "chrome/common/extensions/extension_icon_set.h"
+#include "grit/theme_resources.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/gfx/image/image_skia.h"
+
+using extensions::Extension;
+using extensions::IconImage;
+
+namespace {
+
+gfx::ImageSkia GetDefaultIcon() {
+  return *ui::ResourceBundle::GetSharedInstance().GetImageNamed(
+      IDR_EXTENSIONS_FAVICON).ToImageSkia();
+}
+
+}  // namespace
+
+// extension::IconImage wrapper for extension action icons. We need this
+// because ExtensionAction class cannot use extensions::IconImage directly.
+ExtensionActionIconFactory::ExtensionActionIconFactory(
+    const Extension* extension, Observer* observer)
+    : extension_(extension),
+      observer_(observer),
+      last_icon_set_(NULL),
+      last_size_(0) {
+}
+
+ExtensionActionIconFactory::~ExtensionActionIconFactory() {}
+
+// extensions::IconImage::Observer overrides.
+void ExtensionActionIconFactory::OnExtensionIconImageChanged(IconImage* image) {
+  observer_->OnIconUpdated();
+}
+
+gfx::ImageSkia ExtensionActionIconFactory::GetIcon(
+    const ExtensionIconSet* icon_set,
+    int desired_size) {
+  // If icon set hasn't changed, return the present icon.
+  if (icon_.get() && last_icon_set_ == icon_set) {
+    DCHECK_EQ(last_size_, desired_size);

[Jeffrey Yasskin, 2012/09/13 00:23:36]

I don't see a reason to DCHECK that the sizes match when you could just handle
it by re-computing the icon when the size changes.

[tbarzic, 2012/09/13 02:01:01]

Done.

+    return icon_->image_skia();
+  }
+
+  // TODO(tbarzic): Cache old icon, so we don't have to reload it if gets
+  // requested again.
+  icon_.reset(
+      new IconImage(extension_, *icon_set, desired_size, GetDefaultIcon(),
+                    this));
+  last_icon_set_ = icon_set;
+  last_size_ = desired_size;
+
+  return icon_->image_skia();
+}