net: Stop using base::WorkerPool from UploadFileElementReader

net/base/upload_file_element_reader.cc

Index: net/base/upload_file_element_reader.cc
diff --git a/net/base/upload_file_element_reader.cc b/net/base/upload_file_element_reader.cc
index 32cb27ff42e3cc7758129cbd562b51fd9d0c8d93..cdfc95ed35ebaa16a22b3b33dedf858e7cf67d0a 100644
--- a/net/base/upload_file_element_reader.cc
+++ b/net/base/upload_file_element_reader.cc
@@ -8,7 +8,6 @@
 #include "base/file_util.h"
 #include "base/location.h"
 #include "base/task_runner_util.h"
-#include "base/threading/worker_pool.h"
 #include "net/base/file_stream.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
@@ -92,25 +91,33 @@ int ReadInternal(scoped_refptr<IOBuffer> buf,
 
 }  // namespace
 
+UploadFileElementReader::FileStreamDeleter::FileStreamDeleter(
+    base::TaskRunner* task_runner) : task_runner_(task_runner) {}
+
+UploadFileElementReader::FileStreamDeleter::~FileStreamDeleter() {}
+
 void UploadFileElementReader::FileStreamDeleter::operator() (
     FileStream* file_stream) const {
   if (file_stream) {
-    base::WorkerPool::PostTask(FROM_HERE,
-                               base::Bind(&base::DeletePointer<FileStream>,
-                                          file_stream),
-                               true /* task_is_slow */);
+    DCHECK(task_runner_);
+    task_runner_->PostTask(FROM_HERE,
+                           base::Bind(&base::DeletePointer<FileStream>,
+                                      file_stream));
   }
 }
 
 UploadFileElementReader::UploadFileElementReader(
+    base::TaskRunner* task_runner,
     const FilePath& path,
     uint64 range_offset,
     uint64 range_length,
     const base::Time& expected_modification_time)
-    : path_(path),
+    : task_runner_(task_runner),
+      path_(path),
       range_offset_(range_offset),
       range_length_(range_length),
       expected_modification_time_(expected_modification_time),
+      file_stream_(NULL, FileStreamDeleter(task_runner_)),
       content_length_(0),
       bytes_remaining_(0),
       ALLOW_THIS_IN_INITIALIZER_LIST(weak_ptr_factory_(this)) {
@@ -127,10 +134,11 @@ int UploadFileElementReader::Init(const CompletionCallback& callback) {
   DCHECK(!callback.is_null());
   Reset();
 
-  ScopedFileStreamPtr* file_stream = new ScopedFileStreamPtr;
+  ScopedFileStreamPtr* file_stream =
+      new ScopedFileStreamPtr(NULL, FileStreamDeleter(task_runner_));
   uint64* content_length = new uint64;
   const bool posted = base::PostTaskAndReplyWithResult(
-      base::WorkerPool::GetTaskRunner(true /* task_is_slow */),
+      task_runner_,
       FROM_HERE,
       base::Bind(&InitInternal,
                  path_,
@@ -171,7 +179,7 @@ int UploadFileElementReader::Read(IOBuffer* buf,
   // Pass the ownership of file_stream_ to the worker pool to safely perform
   // operation even when |this| is destructed before the read completes.
   const bool posted = base::PostTaskAndReplyWithResult(
-      base::WorkerPool::GetTaskRunner(true /* task_is_slow */),
+      task_runner_,
       FROM_HERE,
       base::Bind(&ReadInternal,
                  scoped_refptr<IOBuffer>(buf),
@@ -249,7 +257,9 @@ int UploadFileElementReaderSync::Init(const CompletionCallback& callback) {
   content_length_ = 0;
   file_stream_.reset();
 
-  UploadFileElementReader::ScopedFileStreamPtr file_stream;
+  // It's safe to pass NULL for |deleter| here because it will not be used.
+  UploadFileElementReader::FileStreamDeleter deleter(NULL);
+  UploadFileElementReader::ScopedFileStreamPtr file_stream(NULL, deleter);
 
   const int result = InitInternal(path_, range_offset_, range_length_,
                                   expected_modification_time_,