Add ChildMessageFilter, a base class for renderer/worker cross-thread MessageFilter

content/child/quota_message_filter.cc

Index: content/child/quota_message_filter.cc
diff --git a/content/child/quota_message_filter.cc b/content/child/quota_message_filter.cc
index 590a9663a458823b367287a360c5ae3c59a1ac28..139be2550deff675625eda80fa407dc53258c962 100644
--- a/content/child/quota_message_filter.cc
+++ b/content/child/quota_message_filter.cc
@@ -4,16 +4,11 @@
 
 #include "content/child/quota_message_filter.h"
 
-#include "base/bind.h"
-#include "base/location.h"
 #include "base/message_loop/message_loop_proxy.h"
-#include "base/pickle.h"
 #include "content/child/quota_dispatcher.h"
 #include "content/child/thread_safe_sender.h"
+#include "content/child/worker_thread_task_runner.h"
 #include "content/common/quota_messages.h"
-#include "webkit/child/worker_task_runner.h"
-
-using webkit_glue::WorkerTaskRunner;
 
 namespace content {
 
@@ -24,30 +19,7 @@ QuotaMessageFilter::QuotaMessageFilter(
       next_request_id_(0) {
 }
 
-bool QuotaMessageFilter::OnMessageReceived(const IPC::Message& msg) {
-  if (IPC_MESSAGE_CLASS(msg) != QuotaMsgStart)
-    return false;
-  int request_id = -1;
-  bool result = PickleIterator(msg).ReadInt(&request_id);
-  DCHECK(result);
-  base::Closure closure = base::Bind(
-      &QuotaMessageFilter::DispatchMessage, this, msg);
-  int thread_id = 0;
-  {
-    base::AutoLock lock(request_id_map_lock_);
-    RequestIdToThreadId::iterator found = request_id_map_.find(request_id);
-    if (found != request_id_map_.end()) {
-      thread_id = found->second;
-      request_id_map_.erase(found);
-    }
-  }
-  if (!thread_id) {
-    main_thread_loop_proxy_->PostTask(FROM_HERE, closure);
-    return true;
-  }
-  WorkerTaskRunner::Instance()->PostTask(thread_id, closure);
-  return true;
-}
+QuotaMessageFilter::~QuotaMessageFilter() {}
 
 int QuotaMessageFilter::GenerateRequestID(int thread_id) {
   base::AutoLock lock(request_id_map_lock_);
@@ -66,11 +38,35 @@ void QuotaMessageFilter::ClearThreadRequests(int thread_id) {
   }
 }
 
-QuotaMessageFilter::~QuotaMessageFilter() {}
+base::TaskRunner* QuotaMessageFilter::OverrideTaskRunnerForMessage(
+    const IPC::Message& msg) {
+  if (IPC_MESSAGE_CLASS(msg) != QuotaMsgStart)
+    return NULL;
+
+  int request_id = -1, thread_id = 0;
+  const bool success = PickleIterator(msg).ReadInt(&request_id);
+  DCHECK(success);
 
-void QuotaMessageFilter::DispatchMessage(const IPC::Message& msg) {
+  {
+    base::AutoLock lock(request_id_map_lock_);
+    RequestIdToThreadId::iterator found = request_id_map_.find(request_id);
+    if (found != request_id_map_.end()) {
+      thread_id = found->second;
+      request_id_map_.erase(found);
+    }
+  }
+
+  if (!thread_id)
+    return main_thread_loop_proxy_.get();
+  return new WorkerThreadTaskRunner(thread_id);
+}
+
+bool QuotaMessageFilter::OnMessageReceived(const IPC::Message& msg) {
+  if (IPC_MESSAGE_CLASS(msg) != QuotaMsgStart)
+    return false;
   QuotaDispatcher::ThreadSpecificInstance(thread_safe_sender_.get(), this)
       ->OnMessageReceived(msg);
+  return true;
 }
 
 }  // namespace content