create iconmanager as singleton class and cleanup code (#1)

* create iconmanager as singleton class and cleanup code

chromium_src/chrome/browser/icon_loader_mac.mm

@@ -0,0 +1,62 @@
+// 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/icon_loader.h"
+
+#import <AppKit/AppKit.h>
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/threading/thread.h"
+#include "ui/gfx/image/image_skia.h"
+#include "ui/gfx/image/image_skia_util_mac.h"
+
+// static
+IconGroupID IconLoader::ReadGroupIDFromFilepath(
+    const base::FilePath& filepath) {
+  return filepath.Extension();
+}
+
+// static
+bool IconLoader::IsIconMutableFromFilepath(const base::FilePath&) {
+  return false;
+}
+
+// static
+content::BrowserThread::ID IconLoader::ReadIconThreadID() {
+  return content::BrowserThread::FILE;
+}
+
+void IconLoader::ReadIcon() {
+  NSString* group = base::SysUTF8ToNSString(group_);
+  NSWorkspace* workspace = [NSWorkspace sharedWorkspace];
+  NSImage* icon = [workspace iconForFileType:group];
+
+  if (icon_size_ == ALL) {
+    // The NSImage already has all sizes.
+    image_.reset(new gfx::Image([icon retain]));
+  } else {
+    NSSize size = NSZeroSize;
+    switch (icon_size_) {
+      case IconLoader::SMALL:
+        size = NSMakeSize(16, 16);
+        break;
+      case IconLoader::NORMAL:
+        size = NSMakeSize(32, 32);
+        break;
+      default:
+        NOTREACHED();
+    }
+    gfx::ImageSkia image_skia(gfx::ImageSkiaFromResizedNSImage(icon, size));
+    if (!image_skia.isNull()) {
+      image_skia.MakeThreadSafe();
+      image_.reset(new gfx::Image(image_skia));
+    }
+  }
+
+  target_task_runner_->PostTask(FROM_HERE,
+                                base::Bind(&IconLoader::NotifyDelegate, this));
+}