Refactor the avatar button/icon class

chrome/browser/ui/views/profiles/avatar_base_button.cc

+// Copyright 2015 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/ui/views/profiles/avatar_base_button.h"
+
+#include "base/files/file_path.h"
+#include "base/strings/string16.h"
+#include "chrome/browser/browser_process.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/browser/ui/browser.h"
+#include "components/signin/core/common/profile_management_switches.h"
+
+AvatarBaseButton::AvatarBaseButton(Browser* browser)
+    : browser_(browser) {
+  g_browser_process->profile_manager()->GetProfileInfoCache().AddObserver(this);
+}
+
+AvatarBaseButton::~AvatarBaseButton() {
+  g_browser_process->profile_manager()->
+      GetProfileInfoCache().RemoveObserver(this);
+}
+
+void AvatarBaseButton::OnProfileAdded(const base::FilePath& profile_path) {
+  Update();
+}
+
+void AvatarBaseButton::OnProfileWasRemoved(
+      const base::FilePath& profile_path,
+      const base::string16& profile_name) {
+  // If deleting the active profile, don't bother updating the avatar
+  // button, as the browser window is being closed anyway.
+  if (browser_->profile()->GetPath() != profile_path)
+    Update();
+}
+
+void AvatarBaseButton::OnProfileNameChanged(
+      const base::FilePath& profile_path,
+      const base::string16& old_profile_name) {
+  if (browser_->profile()->GetPath() == profile_path)
+    Update();
+}
+
+void AvatarBaseButton::OnProfileAvatarChanged(
+      const base::FilePath& profile_path) {
+  if (!switches::IsNewAvatarMenu() &&
+      browser_->profile()->GetPath() == profile_path)
+    Update();
+}
+
+void AvatarBaseButton::OnProfileSupervisedUserIdChanged(
+      const base::FilePath& profile_path) {
+  if (browser_->profile()->GetPath() == profile_path)
+    Update();
+}
+
+void AvatarBaseButton::Update() {
+  NOTREACHED();

[msw, 2015/04/01 01:30:16]

Why not make this pure-virtual?

[yao, 2015/04/10 00:43:32]

Done.

+}