Clean up the IconLoader.

chrome/browser/icon_loader_mac.mm

 // 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();
+IconLoader::IconGroup IconLoader::GroupForFilepath(
+    const base::FilePath& file_path) {
+  return file_path.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) {
@@ skipping 14 matching lines @@
     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));
 }