Reduce usage of MessageLoopProxy in base/

base/prefs/pref_member.cc

Index: base/prefs/pref_member.cc
diff --git a/base/prefs/pref_member.cc b/base/prefs/pref_member.cc
index 4fa616f4fb612bb8bc3c6338d39a7f60a3033700..1983b1f754de17632252a5a584c12c982a6b97fb 100644
--- a/base/prefs/pref_member.cc
+++ b/base/prefs/pref_member.cc
@@ -9,11 +9,11 @@
 #include "base/location.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/prefs/pref_service.h"
+#include "base/sequenced_task_runner.h"
+#include "base/single_thread_task_runner.h"
+#include "base/thread_task_runner_handle.h"
 #include "base/value_conversions.h"
 
-using base::MessageLoopProxy;
-using base::SingleThreadTaskRunner;
-
 namespace subtle {
 
 PrefMemberBase::PrefMemberBase()
@@ -54,13 +54,13 @@ void PrefMemberBase::Destroy() {
   }
 }
 
-void PrefMemberBase::MoveToThread(
-    const scoped_refptr<SingleThreadTaskRunner>& task_runner) {
+void PrefMemberBase::UseAlternateTaskRunner(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   VerifyValuePrefName();
   // Load the value from preferences if it hasn't been loaded so far.
   if (!internal())
     UpdateValueFromPref(base::Closure());
-  internal()->MoveToThread(task_runner);
+  internal()->UseAlternateTaskRunner(task_runner);
 }
 
 void PrefMemberBase::OnPreferenceChanged(PrefService* service,
@@ -95,15 +95,17 @@ void PrefMemberBase::InvokeUnnamedCallback(const base::Closure& callback,
 }
 
 PrefMemberBase::Internal::Internal()
-    : thread_loop_(MessageLoopProxy::current()),
-      is_managed_(false),
-      is_user_modifiable_(false) {
+    : is_managed_(false), is_user_modifiable_(false) {
+  // In unit tests, there may not be a message loop.
+  if (base::ThreadTaskRunnerHandle::IsSet())
+    task_runner_ = base::ThreadTaskRunnerHandle::Get();
 }
 PrefMemberBase::Internal::~Internal() { }
 
 bool PrefMemberBase::Internal::IsOnCorrectThread() const {
   // In unit tests, there may not be a message loop.
-  return thread_loop_.get() == NULL || thread_loop_->BelongsToCurrentThread();
+  return task_runner_.get() == NULL ||
+         task_runner_->RunsTasksOnCurrentThread();
 }
 
 void PrefMemberBase::Internal::UpdateValue(
@@ -119,19 +121,22 @@ void PrefMemberBase::Internal::UpdateValue(
     is_managed_ = is_managed;
     is_user_modifiable_ = is_user_modifiable;
   } else {
-    bool may_run = thread_loop_->PostTask(
+    bool may_run = task_runner_->PostTask(
         FROM_HERE,
-        base::Bind(&PrefMemberBase::Internal::UpdateValue, this,
-                   value.release(), is_managed, is_user_modifiable,
+        base::Bind(&PrefMemberBase::Internal::UpdateValue,
+                   this,
+                   value.release(),
+                   is_managed,
+                   is_user_modifiable,
                    closure_runner.Release()));
     DCHECK(may_run);
   }
 }
 
-void PrefMemberBase::Internal::MoveToThread(
-    const scoped_refptr<SingleThreadTaskRunner>& task_runner) {
+void PrefMemberBase::Internal::UseAlternateTaskRunner(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   CheckOnCorrectThread();
-  thread_loop_ = task_runner;
+  task_runner_ = task_runner;
 }
 
 bool PrefMemberVectorStringUpdate(const base::Value& value,