Unify Android Webview and Chrome's fling

cc/trees/layer_tree_host_impl_unittest.cc

Index: cc/trees/layer_tree_host_impl_unittest.cc
diff --git a/cc/trees/layer_tree_host_impl_unittest.cc b/cc/trees/layer_tree_host_impl_unittest.cc
index 073d5ae1a08814c6621a8e232da88117f927d3a4..26bbec383bc472a230b2569e9d0c3c219fa1d2fe 100644
--- a/cc/trees/layer_tree_host_impl_unittest.cc
+++ b/cc/trees/layer_tree_host_impl_unittest.cc
@@ -3876,7 +3876,8 @@ class TestScrollOffsetDelegate : public LayerScrollOffsetDelegate {
   TestScrollOffsetDelegate()
       : page_scale_factor_(0.f),
         min_page_scale_factor_(-1.f),
-        max_page_scale_factor_(-1.f) {}
+        max_page_scale_factor_(-1.f),
+        needs_animate_(false) {}
 
   ~TestScrollOffsetDelegate() override {}
 
@@ -3886,6 +3887,10 @@ class TestScrollOffsetDelegate : public LayerScrollOffsetDelegate {
 
   bool IsExternalFlingActive() const override { return false; }
 
+  void SetNeedsAnimate(const AnimationCallback&) override {
+    needs_animate_ = true;
+  }
+
   void UpdateRootLayerState(const gfx::ScrollOffset& total_scroll_offset,
                             const gfx::ScrollOffset& max_scroll_offset,
                             const gfx::SizeF& scrollable_size,
@@ -3904,6 +3909,12 @@ class TestScrollOffsetDelegate : public LayerScrollOffsetDelegate {
     set_getter_return_value(last_set_scroll_offset_);
   }
 
+  bool GetAndResetNeedsAnimate() {
+    bool needs_animate = needs_animate_;
+    needs_animate_ = false;
+    return needs_animate;
+  }
+
   gfx::ScrollOffset last_set_scroll_offset() {
     return last_set_scroll_offset_;
   }
@@ -3940,8 +3951,10 @@ class TestScrollOffsetDelegate : public LayerScrollOffsetDelegate {
   float page_scale_factor_;
   float min_page_scale_factor_;
   float max_page_scale_factor_;
+  bool needs_animate_;
 };
 
+// TODO(jdduke): Test root fling animation.
 TEST_F(LayerTreeHostImplTest, RootLayerScrollOffsetDelegation) {
   TestScrollOffsetDelegate scroll_delegate;
   host_impl_->SetViewportSize(gfx::Size(10, 20));