[Android]Increase Scrollbar fade delay on Resize.

cc/layers/layer_impl.cc

 // Copyright 2012 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 "cc/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_argument.h"
 #include "base/json/json_reader.h"
 #include "base/strings/stringprintf.h"
@@ skipping 1257 matching lines @@
   }
   // TODO(wjmaclean) Once we move to a model where the two-viewport model is
   // turned on in all builds, remove the next two lines. For now however, the
   // page scale layer may coincide with the clip layer, and so this is
   // necessary.
   if (page_scale_layer == scrollbar_clip_layer) {
     scroll_rect.Scale(layer_tree_impl()->total_page_scale_factor());
     current_offset.Scale(layer_tree_impl()->total_page_scale_factor());
   }
 
-  bool scrollbar_needs_animation = false;
-  scrollbar_needs_animation |= scrollbar_layer->SetVerticalAdjust(
+  bool did_scrollbar_position_changed = false;
+  bool did_scrollbar_resize = false;

[aelias_OOO_until_Jul13, 2014/10/03 01:57:53]

Sorry, one more thing.  I just tried it locally and the fade is delayed after
pinches and after some normal scrolls (when the top controls hide), because they
resize the clip layer.  Please make it only use the long fade when the scroll
layer changes size, not when the clip layer does.  You can do that either by
storing the scroll layer size on the scrollbar_layer, or something more like
your original approach of passing a bool to SetScrollbarPosition.

[MuVen, 2014/10/03 13:01:37]

Done.

+  did_scrollbar_position_changed |= scrollbar_layer->SetVerticalAdjust(
       scrollbar_clip_layer->bounds_delta().y());
   if (scrollbar_layer->orientation() == HORIZONTAL) {
     float visible_ratio = clip_rect.width() / scroll_rect.width();
-    scrollbar_needs_animation |=
+    did_scrollbar_position_changed |=
         scrollbar_layer->SetCurrentPos(current_offset.x());
-    scrollbar_needs_animation |=
+    did_scrollbar_resize |=
         scrollbar_layer->SetMaximum(scroll_rect.width() - clip_rect.width());
-    scrollbar_needs_animation |=
+    did_scrollbar_resize |=
         scrollbar_layer->SetVisibleToTotalLengthRatio(visible_ratio);
   } else {
     float visible_ratio = clip_rect.height() / scroll_rect.height();
-    scrollbar_needs_animation |=
+    did_scrollbar_position_changed |=
         scrollbar_layer->SetCurrentPos(current_offset.y());
-    scrollbar_needs_animation |=
+    did_scrollbar_resize |=
         scrollbar_layer->SetMaximum(scroll_rect.height() - clip_rect.height());
-    scrollbar_needs_animation |=
+    did_scrollbar_resize |=
         scrollbar_layer->SetVisibleToTotalLengthRatio(visible_ratio);
   }
-  if (scrollbar_needs_animation) {
+  if (did_scrollbar_position_changed || did_scrollbar_resize) {
     layer_tree_impl()->set_needs_update_draw_properties();
     // TODO(wjmaclean) The scrollbar animator for the pinch-zoom scrollbars
     // should activate for every scroll on the main frame, not just the
     // scrolls that move the pinch virtual viewport (i.e. trigger from
     // either inner or outer viewport).
     if (scrollbar_animation_controller_) {
       // When both non-overlay and overlay scrollbars are both present, don't
       // animate the overlay scrollbars when page scale factor is at the min.
       // Non-overlay scrollbars also shouldn't trigger animations.
       bool is_animatable_scrollbar =
           scrollbar_layer->is_overlay_scrollbar() &&
           ((layer_tree_impl()->total_page_scale_factor() >
             layer_tree_impl()->min_page_scale_factor()) ||
            !layer_tree_impl()->settings().use_pinch_zoom_scrollbars);
       if (is_animatable_scrollbar)
-        scrollbar_animation_controller_->DidScrollUpdate();
+        scrollbar_animation_controller_->DidScrollUpdate(did_scrollbar_resize);
     }
   }
 }
 
 void LayerImpl::DidBecomeActive() {
   if (layer_tree_impl_->settings().scrollbar_animator ==
       LayerTreeSettings::NoAnimator) {
     return;
   }
 
@@ skipping 224 matching lines @@
 }
 
 void LayerImpl::NotifyAnimationFinished(
     base::TimeTicks monotonic_time,
     Animation::TargetProperty target_property) {
   if (target_property == Animation::ScrollOffset)
     layer_tree_impl_->InputScrollAnimationFinished();
 }
 
 }  // namespace cc