Fix UpdateTilePriorities viewport in Android WebView.

cc/trees/layer_tree_impl.cc

Index: cc/trees/layer_tree_impl.cc
diff --git a/cc/trees/layer_tree_impl.cc b/cc/trees/layer_tree_impl.cc
index 52a539b94f461e920800d4421991b37e3283012a..7da2b7e795cb0f33925d4b3f61bf45bc06c1efaf 100644
--- a/cc/trees/layer_tree_impl.cc
+++ b/cc/trees/layer_tree_impl.cc
@@ -207,7 +207,7 @@ void LayerTreeImpl::SetPageScaleDelta(float delta) {
 }
 
 gfx::SizeF LayerTreeImpl::ScrollableViewportSize() const {
-  return gfx::ScaleSize(layer_tree_host_impl_->VisibleViewportSize(),
+  return gfx::ScaleSize(layer_tree_host_impl_->UnscaledScrollableViewportSize(),
                         1.0f / total_page_scale_factor());
 }
 
@@ -272,8 +272,9 @@ void LayerTreeImpl::UpdateSolidColorScrollbars() {
       ScrollableViewportSize());
   float vertical_adjust = 0.0f;
   if (RootContainerLayer())
-    vertical_adjust = layer_tree_host_impl_->VisibleViewportSize().height() -
-                      RootContainerLayer()->bounds().height();
+    vertical_adjust =
+        layer_tree_host_impl_->UnscaledScrollableViewportSize().height() -
+        RootContainerLayer()->bounds().height();
   if (ScrollbarLayerImplBase* horiz =
           root_scroll->horizontal_scrollbar_layer()) {
     horiz->SetVerticalAdjust(vertical_adjust);
@@ -454,6 +455,10 @@ MemoryHistory* LayerTreeImpl::memory_history() const {
   return layer_tree_host_impl_->memory_history();
 }
 
+bool LayerTreeImpl::device_viewport_valid_for_tile_management() const {
+  return layer_tree_host_impl_->device_viewport_valid_for_tile_management();
+}
+
 bool LayerTreeImpl::IsActiveTree() const {
   return layer_tree_host_impl_->active_tree() == this;
 }
@@ -504,6 +509,10 @@ void LayerTreeImpl::SetNeedsCommit() {
   layer_tree_host_impl_->SetNeedsCommit();
 }
 
+gfx::Rect LayerTreeImpl::DeviceViewport() const {
+  return layer_tree_host_impl_->DeviceViewport();
+}
+
 void LayerTreeImpl::SetNeedsRedraw() {
   layer_tree_host_impl_->SetNeedsRedraw();
 }
@@ -516,10 +525,6 @@ float LayerTreeImpl::device_scale_factor() const {
   return layer_tree_host_impl_->device_scale_factor();
 }
 
-gfx::Size LayerTreeImpl::device_viewport_size() const {
-  return layer_tree_host_impl_->device_viewport_size();
-}
-
 DebugRectHistory* LayerTreeImpl::debug_rect_history() const {
   return layer_tree_host_impl_->debug_rect_history();
 }