Fix janky experimental app list animation.

ui/app_list/views/contents_animator.cc

 // Copyright 2014 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 "ui/app_list/views/contents_animator.h"
 
 #include "ui/app_list/app_list_constants.h"
 #include "ui/app_list/app_list_switches.h"
 #include "ui/app_list/views/app_list_main_view.h"
 #include "ui/app_list/views/contents_view.h"
 #include "ui/app_list/views/search_box_view.h"
 #include "ui/app_list/views/start_page_view.h"
 #include "ui/gfx/animation/tween.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace app_list {
 
 // ContentsAnimator
 
 ContentsAnimator::ContentsAnimator(ContentsView* contents_view)
     : contents_view_(contents_view) {
 }
 
 ContentsAnimator::~ContentsAnimator() {
 }
 
 gfx::Rect ContentsAnimator::GetOnscreenPageBounds(int page_index) const {
-  return contents_view_->IsStateActive(AppListModel::STATE_CUSTOM_LAUNCHER_PAGE)
+  return contents_view_->GetPageIndexForState(
+             AppListModel::STATE_CUSTOM_LAUNCHER_PAGE) == page_index
              ? contents_view_->GetContentsBounds()
              : contents_view_->GetDefaultContentsBounds();
 }
 
 gfx::Rect ContentsAnimator::GetOffscreenPageBounds(int page_index) const {
-  gfx::Rect bounds(contents_view_->GetContentsBounds());
+  gfx::Rect bounds(GetOnscreenPageBounds(page_index));
   // The start page and search page origins are above; all other pages' origins
   // are below.
-  int page_height = bounds.height();
   bool origin_above = contents_view_->GetPageIndexForState(
                           AppListModel::STATE_START) == page_index ||
                       contents_view_->GetPageIndexForState(
                           AppListModel::STATE_SEARCH_RESULTS) == page_index;
-  bounds.set_y(origin_above ? -page_height : page_height);
+  bounds.set_y(origin_above
+                   ? -bounds.height()
+                   : contents_view_->GetContentsBounds().height() + bounds.y());
   return bounds;
 }
 
 void ContentsAnimator::UpdateCustomPageForDefaultAnimation(double progress,
                                                            int from_page,
                                                            int to_page) const {
   int custom_page_index = contents_view()->GetPageIndexForState(
       AppListModel::STATE_CUSTOM_LAUNCHER_PAGE);
   if (custom_page_index < 0)
     return;
@@ skipping 145 matching lines @@
   gfx::Rect custom_page_rect(gfx::Tween::RectValueBetween(
       progress, custom_page_origin, custom_page_on_screen));
 
   contents_view()->GetPageView(start_page)->SetBoundsRect(start_page_rect);
   contents_view()->GetPageView(custom_page)->SetBoundsRect(custom_page_rect);
 
   UpdateSearchBoxForDefaultAnimation(progress, start_page, custom_page);
 }
 
 }  // namespace app_list