Enable partial texture upload support for browser compositor with Surfaces

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 fe85134336c21be3891e6fa31f9b5cb0285e7c4f..82328c94c7ca44c6f0f053d7adf399ce3eabd4b5 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -291,6 +291,12 @@ void LayerTreeHostImpl::BeginMainFrameAborted(CommitEarlyOutReason reason) {
 void LayerTreeHostImpl::BeginCommit() {
   TRACE_EVENT0("cc", "LayerTreeHostImpl::BeginCommit");
 
+  // Ensure all textures are returned so partial texture updates can happen
+  // during the commit. Impl-side-painting doesn't upload during commits, so
+  // is unaffected.
+  if (!settings_.impl_side_painting)
+    output_surface_->ForceReclaimResources();
+
   if (UsePendingTreeForSync())
     CreatePendingTree();
 }