Support using TrackedCallbacks as hints to determine the handling thread of resource reply messages

ppapi/proxy/plugin_message_filter.cc

Index: ppapi/proxy/plugin_message_filter.cc
diff --git a/ppapi/proxy/plugin_message_filter.cc b/ppapi/proxy/plugin_message_filter.cc
index 9f178f15acc67f0c5adc8bc077460d8d44497934..68d4cac5fbd71e148f901b4189816b26cc03682f 100644
--- a/ppapi/proxy/plugin_message_filter.cc
+++ b/ppapi/proxy/plugin_message_filter.cc
@@ -4,14 +4,24 @@
 
 #include "ppapi/proxy/plugin_message_filter.h"
 
+#include "base/bind.h"
+#include "base/logging.h"
 #include "ppapi/proxy/ppapi_messages.h"
+#include "ppapi/proxy/resource_message_params.h"
+#include "ppapi/proxy/resource_reply_thread_registrar.h"
+#include "ppapi/shared_impl/ppapi_globals.h"
+#include "ppapi/shared_impl/proxy_lock.h"
+#include "ppapi/shared_impl/resource.h"
+#include "ppapi/shared_impl/resource_tracker.h"
 
 namespace ppapi {
 namespace proxy {
 
 PluginMessageFilter::PluginMessageFilter(
-    std::set<PP_Instance>* seen_instance_ids)
+    std::set<PP_Instance>* seen_instance_ids,
+    scoped_refptr<ResourceReplyThreadRegistrar> registrar)
     : seen_instance_ids_(seen_instance_ids),
+      resource_reply_thread_registrar_(registrar),
       channel_(NULL) {
 }
 
@@ -30,6 +40,7 @@ bool PluginMessageFilter::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PluginMessageFilter, message)
     IPC_MESSAGE_HANDLER(PpapiMsg_ReserveInstanceId, OnMsgReserveInstanceId)
+    IPC_MESSAGE_HANDLER(PpapiPluginMsg_ResourceReply, OnMsgResourceReply)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
@@ -42,6 +53,13 @@ bool PluginMessageFilter::Send(IPC::Message* msg) {
   return false;
 }
 
+// static
+void PluginMessageFilter::DispatchResourceReplyForTest(
+      const ResourceMessageReplyParams& reply_params,
+      const IPC::Message& nested_msg) {
+  DispatchResourceReply(reply_params, nested_msg);
+}
+
 void PluginMessageFilter::OnMsgReserveInstanceId(PP_Instance instance,
                                                  bool* usable) {
   // See the message definition for how this works.
@@ -57,5 +75,37 @@ void PluginMessageFilter::OnMsgReserveInstanceId(PP_Instance instance,
   *usable = true;
 }
 
+void PluginMessageFilter::OnMsgResourceReply(
+    const ResourceMessageReplyParams& reply_params,
+    const IPC::Message& nested_msg) {
+  // TODO(yzshen): Bind() will do an extra copy, do I need to somehow eliminate
+  // it? Compare with the previous code.
+  scoped_refptr<base::MessageLoopProxy> target =
+      resource_reply_thread_registrar_->GetTargetThread(
+          reply_params.pp_resource(), reply_params.sequence());
+
+  target->PostTask(
+      FROM_HERE,
+      base::Bind(&DispatchResourceReply, reply_params, nested_msg));
+}
+
+// TODO(yzshen): I think new resources in in-process mode don't use plugin
+// dispatcher, make sure that is right.
+// static
+void PluginMessageFilter::DispatchResourceReply(
+    const ResourceMessageReplyParams& reply_params,
+    const IPC::Message& nested_msg) {
+  ProxyAutoLock lock;
+  Resource* resource = PpapiGlobals::Get()->GetResourceTracker()->GetResource(
+      reply_params.pp_resource());
+  if (!resource) {
+    DVLOG_IF(1, reply_params.sequence() != 0)
+        << "Pepper resource reply message received but the resource doesn't "
+           "exist (probably has been destroyed).";
+    return;
+  }
+  resource->OnReplyReceived(reply_params, nested_msg);
+}
+
 }  // namespace proxy
 }  // namespace ppapi