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

chrome/browser/gtk/download_started_animation_gtk.cc

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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/download/download_started_animation.h"
 
 #include <gtk/gtk.h>
 
-#include "app/animation.h"
+#include "app/linear_animation.h"
 #include "app/resource_bundle.h"
 #include "base/message_loop.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/notification_registrar.h"
 #include "chrome/common/notification_service.h"
 #include "gfx/rect.h"
 #include "grit/theme_resources.h"
 
 namespace {
 
 // How long to spend moving downwards and fading out after waiting.
 const int kMoveTimeMs = 600;
 
 // The animation framerate.
 const int kFrameRateHz = 60;
 
 // What fraction of the frame height to move downward from the frame center.
 // Note that setting this greater than 0.5 will mean moving past the bottom of
 // the frame.
 const double kMoveFraction = 1.0 / 3.0;
 
-class DownloadStartedAnimationGtk : public Animation,
+class DownloadStartedAnimationGtk : public LinearAnimation,
                                     public NotificationObserver {
  public:
   explicit DownloadStartedAnimationGtk(TabContents* tab_contents);
 
   // DownloadStartedAnimation will delete itself, but this is public so
   // that we can use DeleteSoon().
   virtual ~DownloadStartedAnimationGtk();
 
  private:
   // Move the arrow to wherever it should currently be.
@@ skipping 29 matching lines @@
   gfx::Rect tab_contents_bounds_;
 
   // A scoped container for notification registries.
   NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadStartedAnimationGtk);
 };
 
 DownloadStartedAnimationGtk::DownloadStartedAnimationGtk(
     TabContents* tab_contents)
-    : Animation(kMoveTimeMs, kFrameRateHz, NULL),
+    : LinearAnimation(kMoveTimeMs, kFrameRateHz, NULL),
       tab_contents_(tab_contents) {
   static GdkPixbuf* kDownloadImage = NULL;
   if (!kDownloadImage) {
     ResourceBundle& rb = ResourceBundle::GetSharedInstance();
     kDownloadImage = rb.GetPixbufNamed(IDR_DOWNLOAD_ANIMATION_BEGIN);
   }
 
   width_ = gdk_pixbuf_get_width(kDownloadImage);
   height_ = gdk_pixbuf_get_height(kDownloadImage);
 
@@ skipping 93 matching lines @@
   Close();
 }
 
 }  // namespace
 
 // static
 void DownloadStartedAnimation::Show(TabContents* tab_contents) {
   // The animation will delete itself.
   new DownloadStartedAnimationGtk(tab_contents);
 }