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

content/child/indexed_db/indexed_db_message_filter.h

Index: content/child/indexed_db/indexed_db_message_filter.h
diff --git a/content/child/indexed_db/indexed_db_message_filter.h b/content/child/indexed_db/indexed_db_message_filter.h
index e2d1ed541d77db6fdff190eb2513f831f8240695..08e3998280e8d53825ab195bd00410821baef49d 100644
--- a/content/child/indexed_db/indexed_db_message_filter.h
+++ b/content/child/indexed_db/indexed_db_message_filter.h
@@ -6,7 +6,7 @@
 #define CONTENT_CHILD_INDEXED_DB_INDEXED_DB_MESSAGE_FILTER_H_
 
 #include "base/memory/ref_counted.h"
-#include "content/child/child_message_filter.h"
+#include "content/child/worker_thread_message_filter.h"
 
 struct IndexedDBDatabaseMetadata;
 struct IndexedDBMsg_CallbacksUpgradeNeeded_Params;
@@ -15,15 +15,9 @@ namespace base {
 class MessageLoopProxy;
 }
 
-namespace IPC {
-class Message;
-}
-
 namespace content {
 
-class ThreadSafeSender;
-
-class IndexedDBMessageFilter : public ChildMessageFilter {
+class IndexedDBMessageFilter : public WorkerThreadMessageFilter {
  public:
   explicit IndexedDBMessageFilter(ThreadSafeSender* thread_safe_sender);
 
@@ -31,10 +25,13 @@ class IndexedDBMessageFilter : public ChildMessageFilter {
   ~IndexedDBMessageFilter() override;
 
  private:
-  // ChildMessageFilter implementation:
-  base::TaskRunner* OverrideTaskRunnerForMessage(
-      const IPC::Message& msg) override;
-  bool OnMessageReceived(const IPC::Message& msg) override;
+  // 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;
+
+  // ChildMessageFilter:
   void OnStaleMessageReceived(const IPC::Message& msg) override;
 
   void OnStaleSuccessIDBDatabase(int32 ipc_thread_id,
@@ -44,9 +41,6 @@ class IndexedDBMessageFilter : public ChildMessageFilter {
                                  const IndexedDBDatabaseMetadata&);
   void OnStaleUpgradeNeeded(const IndexedDBMsg_CallbacksUpgradeNeeded_Params&);
 
-  scoped_refptr<base::MessageLoopProxy> main_thread_loop_;
-  scoped_refptr<ThreadSafeSender> thread_safe_sender_;
-
   DISALLOW_COPY_AND_ASSIGN(IndexedDBMessageFilter);
 };