cc: Remove the software compositing bool from PrepareTextureMailbox

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 7d1e14229eb40d34b8d58f648181491170d81cd9..9bcfdd4d6e8714d5ccc25f4c885952ca5111e2cf 100644
--- a/cc/layers/texture_layer.cc
+++ b/cc/layers/texture_layer.cc
@@ -185,10 +185,7 @@ bool TextureLayer::Update() {
   if (client_) {
     TextureMailbox mailbox;
     std::unique_ptr<SingleReleaseCallback> release_callback;
-    if (client_->PrepareTextureMailbox(
-            &mailbox,
-            &release_callback,
-            layer_tree_host()->UsingSharedMemoryResources())) {
+    if (client_->PrepareTextureMailbox(&mailbox, &release_callback)) {
       // Already within a commit, no need to do another one immediately.
       bool requires_commit = false;
       bool allow_mailbox_reuse = false;