Use ash NetworkIconAnimation in NetworkMenuIcon code

ash/system/chromeos/network/network_icon_animation.cc

Index: ash/system/chromeos/network/network_icon_animation.cc
diff --git a/ash/system/chromeos/network/network_icon_animation.cc b/ash/system/chromeos/network/network_icon_animation.cc
new file mode 100644
index 0000000000000000000000000000000000000000..55cc7f03c53346da50abedc5f7bac354dbb781cc
--- /dev/null
+++ b/ash/system/chromeos/network/network_icon_animation.cc
@@ -0,0 +1,59 @@
+// Copyright (c) 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 "ash/system/chromeos/network/network_icon_animation.h"
+
+#include "ash/system/chromeos/network/network_icon_animation_observer.h"
+
+namespace {
+const int kThrobDurationMs = 750;  // Animation cycle length.
+}
+
+namespace ash {
+namespace network_icon {
+
+NetworkIconAnimation::NetworkIconAnimation()
+    : ALLOW_THIS_IN_INITIALIZER_LIST(animation_(this)) {
+  // Set up the animation throbber.
+  animation_.SetThrobDuration(kThrobDurationMs);
+  animation_.SetTweenType(ui::Tween::LINEAR);
+}
+
+NetworkIconAnimation::~NetworkIconAnimation() {
+}
+
+void NetworkIconAnimation::AnimationProgressed(const ui::Animation* animation) {
+  if (animation != &animation_)
+    return;
+  FOR_EACH_OBSERVER(AnimationObserver, observers_, NetworkIconChanged());
+}
+
+double NetworkIconAnimation::GetAnimation() {
+  if (!animation_.is_animating()) {
+    animation_.Reset();
+    animation_.StartThrobbing(-1 /*throb indefinitely*/);
+    return 0;
+  }
+  return animation_.GetCurrentValue();
+}
+
+void NetworkIconAnimation::AddObserver(AnimationObserver* observer) {
+  observers_.AddObserver(observer);
+}
+
+void NetworkIconAnimation::RemoveObserver(AnimationObserver* observer) {
+  observers_.RemoveObserver(observer);
+  if (observers_.size() == 0)
+    animation_.Stop();
+}
+
+// static
+NetworkIconAnimation* NetworkIconAnimation::GetInstance() {
+  static NetworkIconAnimation* s_icon_animation =
+      new NetworkIconAnimation();

[jennyz, 2013/01/31 19:16:50]

A little bit concern about using static for singleton instance here, since the
object will stay in memory once it is used, and no one is going to clean it up
until the system exit. I am not sure if any of the our memory bot will complain
about this or not. 

[stevenjb, 2013/01/31 19:37:42]

We already use this same model in a number of places, e.g.
NetworkMenuIcon::GetImage(). I'll double check with oshima, but this is just
moved from network_icon.cc.

[stevenjb, 2013/01/31 19:41:03]

Confirmed with oshima that this is OK.

+  return s_icon_animation;
+}
+
+}  // namespace network_icon
+}  // namespace ash