[Android] Implementation of overscroll effect for Android L

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index cf5cf24dd0e35a13c7f17ea94b49741ceeb9a070..d20841c250ab88f0b3819f627a6490126b462a80 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -129,19 +129,18 @@ OverscrollGlow::DisplayParameters CreateOverscrollDisplayParameters(
   OverscrollGlow::DisplayParameters params;
   params.size = gfx::ScaleSize(
       frame_metadata.scrollable_viewport_size, scale_factor);
-  params.edge_offsets[EdgeEffect::EDGE_TOP] =
+  params.edge_offsets[OverscrollGlow::EDGE_TOP] =
       -frame_metadata.root_scroll_offset.y() * scale_factor;
-  params.edge_offsets[EdgeEffect::EDGE_LEFT] =
+  params.edge_offsets[OverscrollGlow::EDGE_LEFT] =
       -frame_metadata.root_scroll_offset.x() * scale_factor;
-  params.edge_offsets[EdgeEffect::EDGE_BOTTOM] =
+  params.edge_offsets[OverscrollGlow::EDGE_BOTTOM] =
       (frame_metadata.root_layer_size.height() -
        frame_metadata.root_scroll_offset.y() -
        frame_metadata.scrollable_viewport_size.height()) * scale_factor;
-  params.edge_offsets[EdgeEffect::EDGE_RIGHT] =
+  params.edge_offsets[OverscrollGlow::EDGE_RIGHT] =
       (frame_metadata.root_layer_size.width() -
        frame_metadata.root_scroll_offset.x() -
        frame_metadata.scrollable_viewport_size.width()) * scale_factor;
-  params.device_scale_factor = frame_metadata.device_scale_factor;
 
   return params;
 }
@@ -1111,12 +1110,25 @@ void RenderWidgetHostViewAndroid::ProcessAckedTouchEvent(
 void RenderWidgetHostViewAndroid::GestureEventAck(
     const blink::WebGestureEvent& event,
     InputEventAckState ack_result) {
+  // The overscroll effect requires an explicit release signal that may not be
+  // sent from the renderer compositor.
+  if (event.type == blink::WebInputEvent::GestureScrollEnd ||
+      event.type == blink::WebInputEvent::GestureFlingStart) {
+    DidOverscroll(DidOverscrollParams());
+  }
+
   if (content_view_core_)
     content_view_core_->OnGestureEventAck(event, ack_result);
 }
 
 InputEventAckState RenderWidgetHostViewAndroid::FilterInputEvent(
     const blink::WebInputEvent& input_event) {
+  if (input_event.type == blink::WebInputEvent::GestureScrollUpdate) {
+    const blink::WebGestureEvent& gesture =
+        static_cast<const blink::WebGestureEvent&>(input_event);
+    last_scroll_update_position_ = gfx::PointF(gesture.x, gesture.y);
+  }
+
   if (content_view_core_ &&
       content_view_core_->FilterInputEvent(input_event))
     return INPUT_EVENT_ACK_STATE_CONSUMED;
@@ -1242,6 +1254,8 @@ void RenderWidgetHostViewAndroid::DidOverscroll(
           gfx::ScaleVector2d(params.latest_overscroll_delta,
                              device_scale_factor),
           gfx::ScaleVector2d(params.current_fling_velocity,
+                             device_scale_factor),
+          gfx::ScaleVector2d(last_scroll_update_position_.OffsetFromOrigin(),
                              device_scale_factor))) {
     SetNeedsAnimate();
   }