Convert media constants to constexpr.

chromecast/media/cma/base/balanced_media_task_runner_factory.cc

Index: chromecast/media/cma/base/balanced_media_task_runner_factory.cc
diff --git a/chromecast/media/cma/base/balanced_media_task_runner_factory.cc b/chromecast/media/cma/base/balanced_media_task_runner_factory.cc
index 6a6af62135ad2971b271d6204e065b62fdea1501..845f3d8997b08e8e6c4a96c13fb473d911e58ede 100644
--- a/chromecast/media/cma/base/balanced_media_task_runner_factory.cc
+++ b/chromecast/media/cma/base/balanced_media_task_runner_factory.cc
@@ -90,7 +90,7 @@ class BalancedMediaTaskRunner
   void ScheduleWork(base::TimeDelta max_timestamp);
 
   // Return the timestamp of the last media task.
-  // Return ::media::kNoTimestamp() if no media task has been posted.
+  // Return ::media::kNoTimestamp if no media task has been posted.
   base::TimeDelta GetMediaTimestamp() const;
 
   // MediaTaskRunner implementation.
@@ -112,7 +112,7 @@ class BalancedMediaTaskRunner
   base::Closure pending_task_;
 
   // Timestamp of the last posted task.
-  // Is initialized to ::media::kNoTimestamp().
+  // Is initialized to ::media::kNoTimestamp.
   base::TimeDelta last_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(BalancedMediaTaskRunner);
@@ -120,9 +120,7 @@ class BalancedMediaTaskRunner
 
 BalancedMediaTaskRunner::BalancedMediaTaskRunner(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner)
-  : task_runner_(task_runner),
-    last_timestamp_(::media::kNoTimestamp()) {
-}
+    : task_runner_(task_runner), last_timestamp_(::media::kNoTimestamp) {}
 
 BalancedMediaTaskRunner::~BalancedMediaTaskRunner() {
 }
@@ -134,7 +132,7 @@ void BalancedMediaTaskRunner::ScheduleWork(base::TimeDelta max_media_time) {
     if (pending_task_.is_null())
       return;
 
-    if (last_timestamp_ != ::media::kNoTimestamp() &&
+    if (last_timestamp_ != ::media::kNoTimestamp &&
         last_timestamp_ >= max_media_time) {
       return;
     }
@@ -156,7 +154,7 @@ bool BalancedMediaTaskRunner::PostMediaTask(
   DCHECK(!task.is_null());
 
   // Pass through for a task with no timestamp.
-  if (timestamp == ::media::kNoTimestamp()) {
+  if (timestamp == ::media::kNoTimestamp) {
     return task_runner_->PostTask(from_here, task);
   }
 
@@ -164,8 +162,7 @@ bool BalancedMediaTaskRunner::PostMediaTask(
 
   // Timestamps must be in order.
   // Any task that does not meet that condition is simply discarded.
-  if (last_timestamp_ != ::media::kNoTimestamp() &&
-      timestamp < last_timestamp_) {
+  if (last_timestamp_ != ::media::kNoTimestamp && timestamp < last_timestamp_) {
     return false;
   }
 
@@ -223,7 +220,7 @@ void BalancedMediaTaskRunnerFactory::OnNewTask() {
   for (MediaTaskRunnerSet::const_iterator it = task_runners_.begin();
        it != task_runners_.end(); ++it) {
     base::TimeDelta timestamp((*it)->GetMediaTimestamp());
-    if (timestamp == ::media::kNoTimestamp())
+    if (timestamp == ::media::kNoTimestamp)
       continue;
     runnable_task_runner.insert(
         std::pair<base::TimeDelta, scoped_refptr<BalancedMediaTaskRunner> >(