Convert media constants to constexpr.

media/base/audio_timestamp_helper.cc

 // Copyright (c) 2012 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 "media/base/audio_timestamp_helper.h"
 
 #include "base/logging.h"
 #include "media/base/timestamp_constants.h"
 
 namespace media {
 
 AudioTimestampHelper::AudioTimestampHelper(int samples_per_second)
-    : base_timestamp_(kNoTimestamp()),
-      frame_count_(0) {
+    : base_timestamp_(kNoTimestamp), frame_count_(0) {
   DCHECK_GT(samples_per_second, 0);
   double fps = samples_per_second;
   microseconds_per_frame_ = base::Time::kMicrosecondsPerSecond / fps;
 }
 
 void AudioTimestampHelper::SetBaseTimestamp(base::TimeDelta base_timestamp) {
   base_timestamp_ = base_timestamp;
   frame_count_ = 0;
 }
 
 base::TimeDelta AudioTimestampHelper::base_timestamp() const {
   return base_timestamp_;
 }
 
 void AudioTimestampHelper::AddFrames(int frame_count) {
   DCHECK_GE(frame_count, 0);
-  DCHECK(base_timestamp_ != kNoTimestamp());
+  DCHECK(base_timestamp_ != kNoTimestamp);
   frame_count_ += frame_count;
 }
 
 base::TimeDelta AudioTimestampHelper::GetTimestamp() const {
   return ComputeTimestamp(frame_count_);
 }
 
 base::TimeDelta AudioTimestampHelper::GetFrameDuration(int frame_count) const {
   DCHECK_GE(frame_count, 0);
   base::TimeDelta end_timestamp = ComputeTimestamp(frame_count_ + frame_count);
   return end_timestamp - GetTimestamp();
 }
 
 int64_t AudioTimestampHelper::GetFramesToTarget(base::TimeDelta target) const {
-  DCHECK(base_timestamp_ != kNoTimestamp());
+  DCHECK(base_timestamp_ != kNoTimestamp);
   DCHECK(target >= base_timestamp_);
 
   int64_t delta_in_us = (target - GetTimestamp()).InMicroseconds();
   if (delta_in_us == 0)
     return 0;
 
   // Compute a timestamp relative to |base_timestamp_| since timestamps
   // created from |frame_count_| are computed relative to this base.
   // This ensures that the time to frame computation here is the proper inverse
   // of the frame to time computation in ComputeTimestamp().
   base::TimeDelta delta_from_base = target - base_timestamp_;
 
   // Compute frame count for the time delta. This computation rounds to
   // the nearest whole number of frames.
   double threshold = microseconds_per_frame_ / 2;
   int64_t target_frame_count =
       (delta_from_base.InMicroseconds() + threshold) / microseconds_per_frame_;
   return target_frame_count - frame_count_;
 }
 
 base::TimeDelta AudioTimestampHelper::ComputeTimestamp(
     int64_t frame_count) const {
   DCHECK_GE(frame_count, 0);
-  DCHECK(base_timestamp_ != kNoTimestamp());
+  DCHECK(base_timestamp_ != kNoTimestamp);
   double frames_us = microseconds_per_frame_ * frame_count;
   return base_timestamp_ + base::TimeDelta::FromMicroseconds(frames_us);
 }
 
 }  // namespace media