PPAPI: Implement synchronous postMessage

content/renderer/pepper/resource_converter.cc

Index: content/renderer/pepper/resource_converter.cc
diff --git a/content/renderer/pepper/resource_converter.cc b/content/renderer/pepper/resource_converter.cc
index 4b0c9c990efaaa327bad5d983a47b63ce19dace2..567d7e99ca944a7ee2719f285732604c17ffb69a 100644
--- a/content/renderer/pepper/resource_converter.cc
+++ b/content/renderer/pepper/resource_converter.cc
@@ -275,6 +275,15 @@ void ResourceConverterImpl::Flush(const base::Callback<void(bool)>& callback) {
   browser_vars_.clear();
 }
 
+bool ResourceConverterImpl::FlushSync() {
+  if (!browser_host_create_messages_.empty()) {
+    // TODO(dmichael): Make these work; we have to make a synchronous path to
+    //                 create browser-side hosts. crbug.com/367896
+    return false;
+  }
+  return true;
+}
+
 bool ResourceConverterImpl::ToV8Value(const PP_Var& var,
                                       v8::Handle<v8::Context> context,
                                       v8::Handle<v8::Value>* result) {