Add PDF compositor service

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index 9a4014549bc88ff05171cc8938bf68701d431c42..36556ec4183abaaa1497378a7fced835cbec5fe9 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -93,6 +93,7 @@ class CONTENT_EXPORT ChildThreadImpl
   void RecordComputedAction(const std::string& action) override;
   ServiceManagerConnection* GetServiceManagerConnection() override;
   service_manager::Connector* GetConnector() override;
+  scoped_refptr<base::SingleThreadTaskRunner> GetIOTaskRunner() override;
 
   IPC::SyncChannel* channel() { return channel_.get(); }
 
@@ -190,7 +191,6 @@ class CONTENT_EXPORT ChildThreadImpl
   void OnChannelError() override;
 
   bool IsInBrowserProcess() const;
-  scoped_refptr<base::SingleThreadTaskRunner> GetIOTaskRunner();
 
  private:
   class ChildThreadMessageRouter : public IPC::MessageRouter {