Update the work area bottom when shelf is auto-hide.

This is reland of https://chromium-review.googlesource.com/c/chromium/src/+/721801

Bug: 774617
Change-Id: I047740cedf056198743eb439b183ecb3b0ce3158
Reviewed-on: https://chromium-review.googlesource.com/723671Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: min c <minch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509552}

ui/app_list/views/app_list_view.cc

@@ -1348,8 +1348,8 @@ void AppListView::SetIsInDrag(bool is_in_drag) {
       ->UpdateControlVisibility(app_list_state_, is_in_drag_);
 }
 
-int AppListView::GetWorkAreaBottom() {
-  return fullscreen_widget_->GetWorkAreaBoundsInScreen().bottom();
+int AppListView::GetScreenBottom() {
+  return GetDisplayNearestView().bounds().bottom();
 }
 
 void AppListView::DraggingLayout() {
@@ -1453,7 +1453,8 @@ void AppListView::OnDisplayMetricsChanged(const display::Display& display,
 
 float AppListView::GetAppListBackgroundOpacityDuringDragging() {
   float top_of_applist = fullscreen_widget_->GetWindowBoundsInScreen().y();
-  float dragging_height = std::max((GetWorkAreaBottom() - top_of_applist), 0.f);
+  float dragging_height =
+      std::max((GetScreenBottom() - kShelfSize - top_of_applist), 0.f);
   float coefficient =
       std::min(dragging_height / (kNumOfShelfSize * kShelfSize), 1.0f);
   float shield_opacity =

ui/app_list/views/app_list_view.h

@@ -198,8 +198,8 @@ class APP_LIST_EXPORT AppListView : public views::BubbleDialogDelegateView,
   // screen coordinates.
   gfx::Rect GetAppInfoDialogBounds() const;
 
-  // Gets current work area bottom.
-  int GetWorkAreaBottom();
+  // Gets current screen bottom.
+  int GetScreenBottom();
 
   views::Widget* get_fullscreen_widget_for_test() const {
     return fullscreen_widget_;

ui/app_list/views/apps_container_view.cc

@@ -215,10 +215,9 @@ gfx::Rect AppsContainerView::GetPageBoundsDuringDragging(
     AppListModel::State state) const {
   float app_list_y_position_in_screen =
       contents_view()->app_list_view()->app_list_y_position_in_screen();
-  float work_area_bottom =
-      contents_view()->app_list_view()->GetWorkAreaBottom();
   float drag_amount =
-      std::max(0.f, work_area_bottom - app_list_y_position_in_screen);
+      std::max(0.f, contents_view()->app_list_view()->GetScreenBottom() -
+                        kShelfSize - app_list_y_position_in_screen);
 
   float y = 0;
   float peeking_final_y =
@@ -381,7 +380,7 @@ int AppsContainerView::GetSearchBoxTopPaddingDuringDragging() const {
   float peeking_to_fullscreen_height =
       contents_view()->GetDisplayHeight() - kPeekingAppListHeight;
   float drag_amount = std::max(
-      0, contents_view()->app_list_view()->GetWorkAreaBottom() -
+      0, contents_view()->app_list_view()->GetScreenBottom() - kShelfSize -
              contents_view()->app_list_view()->app_list_y_position_in_screen());
 
   if (drag_amount <= (kPeekingAppListHeight - kShelfSize)) {

ui/app_list/views/apps_grid_view.cc

@@ -1968,7 +1968,7 @@ void AppsGridView::UpdateOpacity() {
   int app_list_y_position_in_screen =
       contents_view_->app_list_view()->app_list_y_position_in_screen();
   AppListView* app_list_view = contents_view_->app_list_view();
-  int work_area_bottom = app_list_view->GetWorkAreaBottom();
+  int screen_bottom = app_list_view->GetScreenBottom();
   bool should_restore_opacity =
       !app_list_view->is_in_drag() &&
       (app_list_view->app_list_state() != AppListView::AppListState::CLOSED);
@@ -1979,7 +1979,8 @@ void AppsGridView::UpdateOpacity() {
   // |kSuggestedAppsOpacityEndFraction|, the opacity of suggested apps changes
   // from 0.f to 1.0f.
   float fraction =
-      std::max<float>(work_area_bottom - app_list_y_position_in_screen, 0) /
+      std::max<float>(
+          screen_bottom - kShelfSize - app_list_y_position_in_screen, 0) /
       (kPeekingAppListHeight - kShelfSize);
   float opacity =
       std::min(std::max((fraction - kSuggestedAppsOpacityStartFraction) /
@@ -2011,8 +2012,8 @@ void AppsGridView::UpdateOpacity() {
   // changes from 0.f to 1.0f.
   float peeking_to_fullscreen_height =
       contents_view_->GetDisplayHeight() - kPeekingAppListHeight;
-  float drag_amount = (work_area_bottom + kShelfSize) -
-                      app_list_y_position_in_screen - kPeekingAppListHeight;
+  float drag_amount =
+      screen_bottom - app_list_y_position_in_screen - kPeekingAppListHeight;
   fraction = std::max(drag_amount / peeking_to_fullscreen_height, 0.f);
   opacity = std::min(std::max((fraction + kAllAppsIndicatorOpacityEndFraction -
                                kAllAppsIndicatorOpacityStartFraction - 1.0f) /
@@ -2037,7 +2038,7 @@ void AppsGridView::UpdateOpacity() {
                1.0f);
   if (expand_arrow_view_) {
     if (app_list_y_position_in_screen <
-        (work_area_bottom + kShelfSize - kPeekingAppListHeight)) {
+        (screen_bottom - kPeekingAppListHeight)) {
       expand_arrow_view_->layer()->SetOpacity(
           should_restore_opacity ? 1.0f : arrow_fullscreen_opacity);
     } else {
@@ -2051,9 +2052,8 @@ void AppsGridView::UpdateOpacity() {
   // of work area and transitioning to 1.0f by the time the centerline reaches
   // |kAllAppsOpacityEndPx| above the work area bottom.
   float centerline_above_work_area = 0.f;
-  const float drag_amount_above_peeking = work_area_bottom + kShelfSize -
-                                          app_list_y_position_in_screen -
-                                          kPeekingAppListHeight;
+  const float drag_amount_above_peeking =
+      screen_bottom - app_list_y_position_in_screen - kPeekingAppListHeight;
   const float opacity_factor = drag_amount_above_peeking / kShelfSize;
   for (int i = 0; i < view_model_.view_size(); ++i) {
     AppListItemView* item_view = GetItemViewAt(i);
@@ -2062,8 +2062,8 @@ void AppsGridView::UpdateOpacity() {
 
     gfx::Rect view_bounds = view_model_.ideal_bounds(i);
     views::View::ConvertRectToScreen(this, &view_bounds);
-    centerline_above_work_area = std::max<float>(
-        work_area_bottom + kShelfSize - view_bounds.CenterPoint().y(), 0.f);
+    centerline_above_work_area =
+        std::max<float>(screen_bottom - view_bounds.CenterPoint().y(), 0.f);
     opacity = std::min(
         std::max((centerline_above_work_area - kAllAppsOpacityStartPx) /
                      (kAllAppsOpacityEndPx - kAllAppsOpacityStartPx),
@@ -2089,8 +2089,8 @@ void AppsGridView::UpdateOpacity() {
   // Updates the opacity of page switcher buttons. The same rule as all apps.
   if (page_switcher_view_) {
     gfx::Rect switcher_bounds = page_switcher_view_->GetBoundsInScreen();
-    centerline_above_work_area = std::max<float>(
-        work_area_bottom + kShelfSize - switcher_bounds.CenterPoint().y(), 0.f);
+    centerline_above_work_area =
+        std::max<float>(screen_bottom - switcher_bounds.CenterPoint().y(), 0.f);
     opacity = std::min(
         std::max((centerline_above_work_area - kAllAppsOpacityStartPx) /
                      (kAllAppsOpacityEndPx - kAllAppsOpacityStartPx),

ui/app_list/views/search_box_view.cc

@@ -747,8 +747,8 @@ void SearchBoxView::UpdateOpacity() {
   int app_list_y_position_in_screen =
       contents_view->app_list_view()->app_list_y_position_in_screen();
   float fraction =
-      std::max<float>(0, contents_view->app_list_view()->GetWorkAreaBottom() -
-                             app_list_y_position_in_screen) /
+      std::max<float>(0, contents_view->app_list_view()->GetScreenBottom() -
+                             kShelfSize - app_list_y_position_in_screen) /
       (kPeekingAppListHeight - kShelfSize);
 
   float opacity =