Teach mojo::Watcher in URLResponseBodyConsumer the correct task runner

content/child/url_response_body_consumer.cc

 // Copyright 2016 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.
 
 #include "content/child/url_response_body_consumer.h"
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "content/child/resource_dispatcher.h"
@@ skipping 26 matching lines @@
 
   scoped_refptr<URLResponseBodyConsumer> consumer_;
 
   DISALLOW_COPY_AND_ASSIGN(ReceivedData);
 };
 
 URLResponseBodyConsumer::URLResponseBodyConsumer(
     int request_id,
     ResourceDispatcher* resource_dispatcher,
     mojo::ScopedDataPipeConsumerHandle handle,
-    base::SingleThreadTaskRunner* task_runner)
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner)
     : request_id_(request_id),
       resource_dispatcher_(resource_dispatcher),
       handle_(std::move(handle)),
+      handle_watcher_(task_runner),
       has_seen_end_of_data_(!handle_.is_valid()) {
   handle_watcher_.Start(
       handle_.get(), MOJO_HANDLE_SIGNAL_READABLE,
       base::Bind(&URLResponseBodyConsumer::OnReadable, base::Unretained(this)));
   task_runner->PostTask(
       FROM_HERE, base::Bind(&URLResponseBodyConsumer::OnReadable, AsWeakPtr(),
                             MOJO_RESULT_OK));
 }
 
 URLResponseBodyConsumer::~URLResponseBodyConsumer() {}
@@ skipping 15 matching lines @@
 void URLResponseBodyConsumer::Reclaim(uint32_t size) {
   MojoResult result = mojo::EndReadDataRaw(handle_.get(), size);
   DCHECK_EQ(MOJO_RESULT_OK, result);
 }
 
 void URLResponseBodyConsumer::OnReadable(MojoResult unused) {
   if (has_been_cancelled_ || has_seen_end_of_data_)
     return;
 
   // TODO(yhirano): Suppress notification when deferred.
-  // TODO(yhirano): Run this operation on the loading task runner.
   while (!has_been_cancelled_) {
     const void* buffer = nullptr;
     uint32_t available = 0;
     MojoResult result = mojo::BeginReadDataRaw(
         handle_.get(), &buffer, &available, MOJO_READ_DATA_FLAG_NONE);
     if (result == MOJO_RESULT_SHOULD_WAIT)
       return;
     if (result == MOJO_RESULT_FAILED_PRECONDITION) {
       has_seen_end_of_data_ = true;
       NotifyCompletionIfAppropriate();
@@ skipping 21 matching lines @@
     return;
   // Cancel this instance in order not to notify twice.
   Cancel();
 
   resource_dispatcher_->OnMessageReceived(
       ResourceMsg_RequestComplete(request_id_, completion_status_));
   // |this| may be deleted.
 }
 
 }  // namespace content