Use per-frame TaskRunner instead of thread's default in DataConsumerHandle

content/child/shared_memory_data_consumer_handle.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_
 #define CONTENT_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
 #include "content/public/child/request_peer.h"
 #include "third_party/WebKit/public/platform/WebDataConsumerHandle.h"
 
+namespace base {
+class SingleThreadTaskRunner;
+}
+
 namespace content {
 
 // This class is a WebDataConsumerHandle that accepts RequestPeer::ReceivedData.
 class CONTENT_EXPORT SharedMemoryDataConsumerHandle final
     : public NON_EXPORTED_BASE(blink::WebDataConsumerHandle) {
  private:
   class Context;
 
  public:
   enum BackpressureMode {
@@ skipping 14 matching lines @@
 
    private:
     scoped_refptr<Context> context_;
     BackpressureMode mode_;
 
     DISALLOW_COPY_AND_ASSIGN(Writer);
   };
 
   class ReaderImpl final : public Reader {
    public:
-    ReaderImpl(scoped_refptr<Context> context, Client* client);
+    ReaderImpl(scoped_refptr<Context> context, Client* client,
+               scoped_refptr<base::SingleThreadTaskRunner> reader_task_runner);
     ~ReaderImpl() override;
     Result read(void* data,
                 size_t size,
                 Flags flags,
                 size_t* readSize) override;
     Result beginRead(const void** buffer,
                      Flags flags,
                      size_t* available) override;
     Result endRead(size_t readSize) override;
 
@@ skipping 10 matching lines @@
   // |on_reader_detached| will be called aynchronously on the calling thread
   // when the reader (including the handle) is detached (i.e. both the handle
   // and the reader are destructed). The callback will be reset in the internal
   // context when the writer is detached, i.e. |Close| or |Fail| is called,
   // and the callback will never be called.
   SharedMemoryDataConsumerHandle(BackpressureMode mode,
                                  const base::Closure& on_reader_detached,
                                  std::unique_ptr<Writer>* writer);
   ~SharedMemoryDataConsumerHandle() override;
 
-  std::unique_ptr<Reader> obtainReader(Client* client) override;
+  // Unlike to other Reader, |reader_task_runner| here is nullable, so that
+  // the test code don't need to create blink::WebTaskRunner.
+  std::unique_ptr<Reader> obtainReader(
+      Client* client,
+      std::unique_ptr<blink::WebTaskRunner> reader_task_runner) override;
 
  private:
   const char* debugName() const override;
 
   scoped_refptr<Context> context_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedMemoryDataConsumerHandle);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_SHARED_MEMORY_DATA_CONSUMER_HANDLE_H_