android webview: allow cc to fail hardware draw

cc/trees/single_thread_proxy.cc

Index: cc/trees/single_thread_proxy.cc
diff --git a/cc/trees/single_thread_proxy.cc b/cc/trees/single_thread_proxy.cc
index 02315481aa7444d7176770f79902291e839bdde9..17c43a2f2b2cbc90f3d48f6bdeaf85377e15863a 100644
--- a/cc/trees/single_thread_proxy.cc
+++ b/cc/trees/single_thread_proxy.cc
@@ -354,6 +354,11 @@ void SingleThreadProxy::Stop() {
   layer_tree_host_ = NULL;
 }
 
+void SingleThreadProxy::OnResourcelessSoftareDrawStateChanged(
+    bool resourceless_draw) {
+  NOTREACHED();
+}
+
 void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
   TRACE_EVENT1(
       "cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);