Reland "Remove hover on icons in launcher"

This is a reland of 517fd5f9
Original change's description:
> Remove hover on icons in launcher
> 
> Changes:
> Disable ImageShadowAnimator in fullscreen app list mode so that the icon
> will not jump when hovered.
> 
> BUG=748236
> 
> Change-Id: Iba8c0717f7cdb132a28c4c21eb9add81a652e93a
> Reviewed-on: https://chromium-review.googlesource.com/592335
> Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
> Commit-Queue: Weidong Guo <weidongg@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#490526}

Bug: 748236
Change-Id: I2721590e0b42a03e87ca277a82b7929124704412
Reviewed-on: https://chromium-review.googlesource.com/593188Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Weidong Guo <weidongg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#490800}

ui/app_list/views/app_list_item_view.cc

@@ -76,10 +76,13 @@ AppListItemView::AppListItemView(AppsGridView* apps_grid_view,
       icon_(new views::ImageView),
       title_(new views::Label),
       progress_bar_(new views::ProgressBar),
-      shadow_animator_(this),
       is_fullscreen_app_list_enabled_(features::IsFullscreenAppListEnabled()) {
-  shadow_animator_.animation()->SetTweenType(gfx::Tween::FAST_OUT_SLOW_IN);
-  shadow_animator_.SetStartAndEndShadows(IconStartShadows(), IconEndShadows());
+  if (!is_fullscreen_app_list_enabled_) {
+    shadow_animator_.reset(new ImageShadowAnimator(this));
+    shadow_animator_->animation()->SetTweenType(gfx::Tween::FAST_OUT_SLOW_IN);
+    shadow_animator_->SetStartAndEndShadows(IconStartShadows(),
+                                            IconEndShadows());
+  }
 
   icon_->set_can_process_events_within_subtree(false);
   icon_->SetVerticalAlignment(views::ImageView::LEADING);
@@ -135,7 +138,10 @@ void AppListItemView::SetIcon(const gfx::ImageSkia& icon) {
       icon,
       skia::ImageOperations::RESIZE_BEST,
       gfx::Size(kGridIconDimension, kGridIconDimension)));
-  shadow_animator_.SetOriginalImage(resized);
+  if (shadow_animator_)
+    shadow_animator_->SetOriginalImage(resized);
+  else
+    icon_->SetImage(resized);
 }
 
 void AppListItemView::SetUIState(UIState ui_state) {
@@ -266,13 +272,15 @@ void AppListItemView::ShowContextMenuForView(views::View* source,
 
 void AppListItemView::StateChanged(ButtonState old_state) {
   if (state() == STATE_HOVERED || state() == STATE_PRESSED) {
-    shadow_animator_.animation()->Show();
+    if (shadow_animator_)
+      shadow_animator_->animation()->Show();
     // Show the hover/tap highlight: for tap, lighter highlight replaces darker
     // keyboard selection; for mouse hover, keyboard selection takes precedence.
     if (!apps_grid_view_->IsSelectedView(this) || state() == STATE_PRESSED)
       SetItemIsHighlighted(true);
   } else {
-    shadow_animator_.animation()->Hide();
+    if (shadow_animator_)
+      shadow_animator_->animation()->Hide();
     SetItemIsHighlighted(false);
     if (item_weak_)
       item_weak_->set_highlighted(false);

ui/app_list/views/app_list_item_view.h

@@ -160,7 +160,7 @@ class APP_LIST_EXPORT AppListItemView : public views::CustomButton,
   // True if scroll gestures should contribute to dragging.
   bool touch_dragging_ = false;
 
-  ImageShadowAnimator shadow_animator_;
+  std::unique_ptr<ImageShadowAnimator> shadow_animator_;
 
   bool is_installing_ = false;
   bool is_highlighted_ = false;