Allow MessageFilters to restrict listening to specific message classes

content/browser/message_port_message_filter.cc

Index: content/browser/message_port_message_filter.cc
diff --git a/content/browser/message_port_message_filter.cc b/content/browser/message_port_message_filter.cc
index 70d8175b503f988c618530b1d5af3f7de57d55ea..60124fbdc442abcb702aa3ea668a38e8007b7e0a 100644
--- a/content/browser/message_port_message_filter.cc
+++ b/content/browser/message_port_message_filter.cc
@@ -8,10 +8,17 @@
 #include "content/common/message_port_messages.h"
 
 namespace content {
+namespace {
+const uint32 kFilteredMessageClasses[] = {
+  MessagePortMsgStart,
+};
+}  // namespace
 
 MessagePortMessageFilter::MessagePortMessageFilter(
     const NextRoutingIDCallback& callback)
-    : next_routing_id_(callback) {
+    : BrowserMessageFilter(
+          kFilteredMessageClasses, arraysize(kFilteredMessageClasses)),
+      next_routing_id_(callback) {
 }
 
 MessagePortMessageFilter::~MessagePortMessageFilter() {