workers: Introduce a WorkerThreadMessageFilter to ease routing/processing worker messages.

Move the task of managing the task-runners for the worker-thread/main-thread in
a common implementation in WorkerThreadMessageFilter, and use that from the rest
of the message filters.

BUG=none
R=jochen@chromium.org, kinuko@chromium.org

Review URL: https://codereview.chromium.org/892543002

Cr-Commit-Position: refs/heads/master@{#314556}

2 files changed, 20 insertions, 35 deletions

diff --git a/content/child/geofencing/geofencing_message_filter.cc b/content/child/geofencing/geofencing_message_filter.cc
index a833457..a866b37 100644
--- a/content/child/geofencing/geofencing_message_filter.cc
+++ b/content/child/geofencing/geofencing_message_filter.cc
@@ -4,40 +4,33 @@
 
 #include "content/child/geofencing/geofencing_message_filter.h"
 
-#include "base/message_loop/message_loop_proxy.h"
 #include "content/child/geofencing/geofencing_dispatcher.h"
-#include "content/child/thread_safe_sender.h"
-#include "content/child/worker_thread_task_runner.h"
 #include "ipc/ipc_message_macros.h"
 
 namespace content {
 
 GeofencingMessageFilter::GeofencingMessageFilter(ThreadSafeSender* sender)
-    : main_thread_loop_proxy_(base::MessageLoopProxy::current()),
-      thread_safe_sender_(sender) {
+    : WorkerThreadMessageFilter(sender) {
 }
 
 GeofencingMessageFilter::~GeofencingMessageFilter() {
 }
 
-base::TaskRunner* GeofencingMessageFilter::OverrideTaskRunnerForMessage(
+bool GeofencingMessageFilter::ShouldHandleMessage(
+    const IPC::Message& msg) const {
+  return IPC_MESSAGE_CLASS(msg) == GeofencingMsgStart;
+}
+
+void GeofencingMessageFilter::OnFilteredMessageReceived(
     const IPC::Message& msg) {
-  if (IPC_MESSAGE_CLASS(msg) != GeofencingMsgStart)
-    return NULL;
-  int ipc_thread_id = 0;
-  const bool success = PickleIterator(msg).ReadInt(&ipc_thread_id);
-  DCHECK(success);
-  if (!ipc_thread_id)
-    return main_thread_loop_proxy_.get();
-  return new WorkerThreadTaskRunner(ipc_thread_id);
+  GeofencingDispatcher::GetOrCreateThreadSpecificInstance(thread_safe_sender())
+      ->OnMessageReceived(msg);
 }
 
-bool GeofencingMessageFilter::OnMessageReceived(const IPC::Message& msg) {
-  if (IPC_MESSAGE_CLASS(msg) != GeofencingMsgStart)
-    return false;
-  GeofencingDispatcher::GetOrCreateThreadSpecificInstance(
-      thread_safe_sender_.get())->OnMessageReceived(msg);
-  return true;
+bool GeofencingMessageFilter::GetWorkerThreadIdForMessage(
+    const IPC::Message& msg,
+    int* ipc_thread_id) {
+  return PickleIterator(msg).ReadInt(ipc_thread_id);
 }
 
 }  // namespace content
diff --git a/content/child/geofencing/geofencing_message_filter.h b/content/child/geofencing/geofencing_message_filter.h
index 3a95d42..34a05c2 100644
--- a/content/child/geofencing/geofencing_message_filter.h
+++ b/content/child/geofencing/geofencing_message_filter.h
@@ -5,30 +5,22 @@
 #ifndef CONTENT_CHILD_GEOFENCING_GEOFENCING_MESSAGE_FILTER_H_
 #define CONTENT_CHILD_GEOFENCING_GEOFENCING_MESSAGE_FILTER_H_
 
-#include "content/child/child_message_filter.h"
-
-namespace base {
-class MessageLoopProxy;
-}
+#include "content/child/worker_thread_message_filter.h"
 
 namespace content {
 
-class ThreadSafeSender;
-
-class GeofencingMessageFilter : public ChildMessageFilter {
+class GeofencingMessageFilter : public WorkerThreadMessageFilter {
  public:
   explicit GeofencingMessageFilter(ThreadSafeSender* thread_safe_sender);
 
  private:
   ~GeofencingMessageFilter() override;
 
-  // ChildMessageFilter implementation:
-  base::TaskRunner* OverrideTaskRunnerForMessage(
-      const IPC::Message& msg) override;
-  bool OnMessageReceived(const IPC::Message& msg) override;
-
-  scoped_refptr<base::MessageLoopProxy> main_thread_loop_proxy_;
-  scoped_refptr<ThreadSafeSender> thread_safe_sender_;
+  // WorkerThreadMessageFilter:
+  bool ShouldHandleMessage(const IPC::Message& msg) const override;
+  void OnFilteredMessageReceived(const IPC::Message& msg) override;
+  bool GetWorkerThreadIdForMessage(const IPC::Message& msg,
+                                   int* ipc_thread_id) override;
 
   DISALLOW_COPY_AND_ASSIGN(GeofencingMessageFilter);
 };