gfx: Make conversions from gfx::Point to PointF explicit.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 02bcb10a9281ee8807dba6456e68dce48a44abb8..92f532f646cc7362885d8ea165288ce7ef68897a 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -509,8 +509,8 @@ bool LayerTreeHostImpl::IsCurrentlyScrollingLayerAt(
   if (!scrolling_layer_impl)
     return false;
 
-  gfx::PointF device_viewport_point =
-      gfx::ScalePoint(viewport_point, active_tree_->device_scale_factor());
+  gfx::PointF device_viewport_point = gfx::ScalePoint(
+      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
 
   LayerImpl* layer_impl =
       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
@@ -538,8 +538,8 @@ bool LayerTreeHostImpl::IsCurrentlyScrollingLayerAt(
 
 bool LayerTreeHostImpl::HaveWheelEventHandlersAt(
     const gfx::Point& viewport_point) {
-  gfx::PointF device_viewport_point =
-      gfx::ScalePoint(viewport_point, active_tree_->device_scale_factor());
+  gfx::PointF device_viewport_point = gfx::ScalePoint(
+      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
 
   LayerImpl* layer_impl =
       active_tree_->FindLayerWithWheelHandlerThatIsHitByPoint(
@@ -565,8 +565,8 @@ static ScrollBlocksOn EffectiveScrollBlocksOn(LayerImpl* layer) {
 
 bool LayerTreeHostImpl::DoTouchEventsBlockScrollAt(
     const gfx::Point& viewport_point) {
-  gfx::PointF device_viewport_point =
-      gfx::ScalePoint(viewport_point, active_tree_->device_scale_factor());
+  gfx::PointF device_viewport_point = gfx::ScalePoint(
+      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
 
   // First check if scrolling at this point is required to block on any
   // touch event handlers.  Note that we must start at the innermost layer
@@ -2426,8 +2426,8 @@ InputHandler::ScrollStatus LayerTreeHostImpl::ScrollBegin(
   DCHECK(!CurrentlyScrollingLayer());
   ClearCurrentlyScrollingLayer();
 
-  gfx::PointF device_viewport_point =
-      gfx::ScalePoint(viewport_point, active_tree_->device_scale_factor());
+  gfx::PointF device_viewport_point = gfx::ScalePoint(
+      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
   LayerImpl* layer_impl =
       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
 
@@ -2582,6 +2582,8 @@ static gfx::Vector2dF ScrollLayerWithLocalDelta(
   return consumed_scroll;
 }
 
+// TODO(danakj): Make this into two functions, one with delta, one with
+// viewport_point, no bool required.
 gfx::Vector2dF LayerTreeHostImpl::ScrollLayer(LayerImpl* layer_impl,
                                               const gfx::Vector2dF& delta,
                                               const gfx::Point& viewport_point,
@@ -2593,8 +2595,10 @@ gfx::Vector2dF LayerTreeHostImpl::ScrollLayer(LayerImpl* layer_impl,
   // screen (such as wheel events) represent a fixed amount of scrolling so we
   // can just apply them directly, but the page scale factor is applied to the
   // scroll delta.
-  if (is_direct_manipulation)
-    return ScrollLayerWithViewportSpaceDelta(layer_impl, viewport_point, delta);
+  if (is_direct_manipulation) {
+    return ScrollLayerWithViewportSpaceDelta(
+        layer_impl, gfx::PointF(viewport_point), delta);
+  }
   float scale_factor = active_tree()->current_page_scale_factor();
   return ScrollLayerWithLocalDelta(layer_impl, delta, scale_factor);
 }
@@ -2840,8 +2844,8 @@ float LayerTreeHostImpl::DeviceSpaceDistanceToLayer(
 }
 
 void LayerTreeHostImpl::MouseMoveAt(const gfx::Point& viewport_point) {
-  gfx::PointF device_viewport_point =
-      gfx::ScalePoint(viewport_point, active_tree_->device_scale_factor());
+  gfx::PointF device_viewport_point = gfx::ScalePoint(
+      gfx::PointF(viewport_point), active_tree_->device_scale_factor());
   LayerImpl* layer_impl =
       active_tree_->FindLayerThatIsHitByPoint(device_viewport_point);
   if (HandleMouseOverScrollbar(layer_impl, device_viewport_point))