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

* create iconmanager as singleton class and cleanup code

chromium_src/chrome/browser/icon_loader_auralinux.cc

@@ -0,0 +1,55 @@
+// Copyright 2013 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"
+
+#include "base/bind.h"
+#include "base/message_loop/message_loop.h"
+#include "base/nix/mime_util_xdg.h"
+#include "ui/views/linux_ui/linux_ui.h"
+
+// static
+IconGroupID IconLoader::ReadGroupIDFromFilepath(
+    const base::FilePath& filepath) {
+  return base::nix::GetFileMimeType(filepath);
+}
+
+// static
+bool IconLoader::IsIconMutableFromFilepath(const base::FilePath&) {
+  return false;
+}
+
+// static
+content::BrowserThread::ID IconLoader::ReadIconThreadID() {
+  // ReadIcon() calls into views::LinuxUI and GTK2 code, so it must be on the UI
+  // thread.
+  return content::BrowserThread::UI;
+}
+
+void IconLoader::ReadIcon() {
+  int size_pixels = 0;
+  switch (icon_size_) {
+    case IconLoader::SMALL:
+      size_pixels = 16;
+      break;
+    case IconLoader::NORMAL:
+      size_pixels = 32;
+      break;
+    case IconLoader::LARGE:
+      size_pixels = 48;
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  views::LinuxUI* ui = views::LinuxUI::instance();
+  if (ui) {
+    gfx::Image image = ui->GetIconForContentType(group_, size_pixels);
+    if (!image.IsEmpty())
+      image_.reset(new gfx::Image(image));
+  }
+
+  target_task_runner_->PostTask(FROM_HERE,
+                                base::Bind(&IconLoader::NotifyDelegate, this));
+}