NOT FOR LANDING - [WebView] Allow fling animation via the LayerScrollOffsetDelegate

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 381 matching lines @@
   if (EvictedUIResourcesExist()) {
     TRACE_EVENT_INSTANT0(
         "cc", "LayerTreeHostImpl::CanDraw UI resources evicted not recreated",
         TRACE_EVENT_SCOPE_THREAD);
     return false;
   }
   return true;
 }
 
 void LayerTreeHostImpl::Animate(base::TimeTicks monotonic_time) {
-  if (input_handler_client_)
-    input_handler_client_->Animate(monotonic_time);
+  AnimateFling(monotonic_time);

[mkosiba (inactive), 2014/05/15 13:48:51]

I don't think we want to call this at all if layer_scroll_offset_delegate is not
null

[jdduke (slow), 2014/05/15 14:15:43]

Oops yeah that's definitely what I had planned.

   AnimatePageScale(monotonic_time);
   AnimateLayers(monotonic_time);
   AnimateScrollbars(monotonic_time);
   AnimateTopControls(monotonic_time);
 }
 
 void LayerTreeHostImpl::ManageTiles() {
   if (!tile_manager_)
     return;
   if (!tile_priorities_dirty_)
@@ skipping 50 matching lines @@
     page_scale_animation_->ZoomTo(scaled_target_offset,
                                   page_scale,
                                   duration.InSecondsF());
   }
 
   SetNeedsAnimate();
   client_->SetNeedsCommitOnImplThread();
   client_->RenewTreePriority();
 }
 
+void LayerTreeHostImpl::SetNeedsAnimateFling() {
+  if (root_layer_scroll_offset_delegate_ &&
+      (CurrentlyScrollingLayer() == InnerViewportScrollLayer() ||
+       CurrentlyScrollingLayer() == OuterViewportScrollLayer())) {
+    // Hacky callback approach...
+    root_layer_scroll_offset_delegate_->SetNeedsAnimate(
+        base::Bind(&LayerTreeHostImpl::AnimateFling, AsWeakPtr()));
+    return;
+  }
+
+  SetNeedsAnimate();
+}
+
 bool LayerTreeHostImpl::IsCurrentlyScrollingLayerAt(
     const gfx::Point& viewport_point,
     InputHandler::ScrollInputType type) {
   if (!CurrentlyScrollingLayer())
     return false;
 
   if (!EnsureRenderSurfaceLayerList())
     return false;
 
   gfx::PointF device_viewport_point =
@@ skipping 2267 matching lines @@
   LayerImpl* scroll_layer = OuterViewportScrollLayer()
                                 ? OuterViewportScrollLayer()
                                 : InnerViewportScrollLayer();
 
   gfx::Vector2dF unused_delta = scroll_layer->ScrollBy(scroll_delta);
 
   if (!unused_delta.IsZero() && (scroll_layer == OuterViewportScrollLayer()))
     InnerViewportScrollLayer()->ScrollBy(unused_delta);
 }
 
+void LayerTreeHostImpl::AnimateFling(base::TimeTicks monotonic_time) {
+  DCHECK(proxy_->IsImplThread());
+  if (input_handler_client_)
+    input_handler_client_->AnimateFling(monotonic_time);
+}
+
 void LayerTreeHostImpl::AnimatePageScale(base::TimeTicks monotonic_time) {
   if (!page_scale_animation_)
     return;
 
   // TODO(ajuma): http://crbug.com/178171 - Animations use double for monotonic
   // time.
   double monotonic_time_for_cc_animations =
       (monotonic_time - base::TimeTicks()).InSecondsF();
   gfx::Vector2dF scroll_total = active_tree_->TotalScrollOffset();
 
@@ skipping 348 matching lines @@
   swap_promise_monitor_.erase(monitor);
 }
 
 void LayerTreeHostImpl::NotifySwapPromiseMonitorsOfSetNeedsRedraw() {
   std::set<SwapPromiseMonitor*>::iterator it = swap_promise_monitor_.begin();
   for (; it != swap_promise_monitor_.end(); it++)
     (*it)->OnSetNeedsRedrawOnImpl();
 }
 
 }  // namespace cc