Moved JsonPrefStore to use SequencedWorkerPool

chrome/common/important_file_writer.cc

Index: chrome/common/important_file_writer.cc
diff --git a/chrome/common/important_file_writer.cc b/chrome/common/important_file_writer.cc
index 6a76dfbb362b83776d0c8f37e0d2bc5176e039df..c77c96f4f64fbd7230a14759600c55a9c3b1b0c2 100644
--- a/chrome/common/important_file_writer.cc
+++ b/chrome/common/important_file_writer.cc
@@ -12,7 +12,7 @@
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
-#include "base/message_loop_proxy.h"
+#include "base/task_runner.h"
 #include "base/metrics/histogram.h"
 #include "base/string_number_conversions.h"
 #include "base/threading/thread.h"
@@ -89,14 +89,14 @@ void WriteToDiskTask(const FilePath& path, const std::string& data) {
 }  // namespace
 
 ImportantFileWriter::ImportantFileWriter(
-    const FilePath& path, base::MessageLoopProxy* file_message_loop_proxy)
+    const FilePath& path, base::SequencedTaskRunner* task_runner)
         : path_(path),
-          file_message_loop_proxy_(file_message_loop_proxy),
+          task_runner_(task_runner),
           serializer_(NULL),
           commit_interval_(TimeDelta::FromMilliseconds(
               kDefaultCommitIntervalMs)) {
   DCHECK(CalledOnValidThread());
-  DCHECK(file_message_loop_proxy_.get());
+  DCHECK(task_runner_.get());
 }
 
 ImportantFileWriter::~ImportantFileWriter() {
@@ -121,7 +121,7 @@ void ImportantFileWriter::WriteNow(const std::string& data) {
   if (HasPendingWrite())
     timer_.Stop();
 
-  if (!file_message_loop_proxy_->PostTask(
+  if (!task_runner_->PostTask(
       FROM_HERE, base::Bind(&WriteToDiskTask, path_, data))) {
     // Posting the task to background message loop is not expected
     // to fail, but if it does, avoid losing data and just hit the disk