Allow WebExternalTextureLayers to receive a bitmap along with a mailbox

cc/layers/texture_layer.cc

Index: cc/layers/texture_layer.cc
diff --git a/cc/layers/texture_layer.cc b/cc/layers/texture_layer.cc
index 9e9dff80584549ff38fd981c222cb9d216691d3c..beda83af8f45e31f5205125e22f7753d0c897a4e 100644
--- a/cc/layers/texture_layer.cc
+++ b/cc/layers/texture_layer.cc
@@ -171,7 +171,8 @@ void TextureLayer::Update(ResourceUpdateQueue* queue,
   if (client_) {
     if (uses_mailbox_) {
       TextureMailbox mailbox;
-      if (client_->PrepareTextureMailbox(&mailbox)) {
+      if (client_->PrepareTextureMailbox(
+              &mailbox, layer_tree_host()->UsingSharedMemoryResources())) {
         if (mailbox.IsTexture())
           DCHECK(client_->Context3d());
         SetTextureMailbox(mailbox);