Bring back setting visible viewport size based on cliprect.

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 1d74dcc07160394bf3524b70b7e66f2576200cd0..43a4b68f314fb4aa84edaba036790c1f198e3787 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1316,6 +1316,15 @@ float LayerTreeHostImpl::DeviceScaleFactor() const {
 }
 
 gfx::SizeF LayerTreeHostImpl::VisibleViewportSize() const {
+  // The container layer bounds should be used if non-overlay scrollbars may
+  // exist since it adjusts for them.
+  LayerImpl* container_layer = active_tree_->RootContainerLayer();
+  if (!Settings().solid_color_scrollbars && container_layer) {
+    DCHECK(!top_controls_manager_);
+    DCHECK_EQ(0, overdraw_bottom_height_);
+    return container_layer->bounds();
+  }
+
   gfx::SizeF dip_size =
       gfx::ScaleSize(device_viewport_size(), 1.f / device_scale_factor());