Refactors animation to allow for cleaner subclassing. I'm doing this

app/animation_container_unittest.cc

Index: app/animation_container_unittest.cc
diff --git a/app/animation_container_unittest.cc b/app/animation_container_unittest.cc
index 4046ae33b1e0b214e6d4c522e00c8f2183125a44..e4253c6a032029783711a3dbf069ed55bdd3d59d 100644
--- a/app/animation_container_unittest.cc
+++ b/app/animation_container_unittest.cc
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "app/animation.h"
 #include "app/animation_container.h"
+#include "app/linear_animation.h"
 #include "app/test_animation_delegate.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -23,10 +23,10 @@ class MockObserver : public AnimationContainer::Observer {
   DISALLOW_COPY_AND_ASSIGN(MockObserver);
 };
 
-class TestAnimation : public Animation {
+class TestAnimation : public LinearAnimation {
  public:
   TestAnimation(AnimationDelegate* delegate)
-      : Animation(20, 20, delegate) {
+      : LinearAnimation(20, 20, delegate) {
   }
 
   virtual void AnimateToState(double state) {