Convert media constants to constexpr.

media/filters/video_renderer_algorithm_unittest.cc

Index: media/filters/video_renderer_algorithm_unittest.cc
diff --git a/media/filters/video_renderer_algorithm_unittest.cc b/media/filters/video_renderer_algorithm_unittest.cc
index 61a1d1681db3e7052cd1f136eb7b7518c399cf87..b6c76589d90a64b2c7c1b4c29c45793f00533b0c 100644
--- a/media/filters/video_renderer_algorithm_unittest.cc
+++ b/media/filters/video_renderer_algorithm_unittest.cc
@@ -185,7 +185,7 @@ class VideoRendererAlgorithmTest : public testing::Test {
 
     const bool fresh_algorithm = !algorithm_.have_rendered_frames_;
 
-    base::TimeDelta last_start_timestamp = kNoTimestamp();
+    base::TimeDelta last_start_timestamp = kNoTimestamp;
     bool should_use_cadence = false;
     int glitch_count = 0;
     const base::TimeTicks start_time = tick_clock_->NowTicks();
@@ -216,7 +216,7 @@ class VideoRendererAlgorithmTest : public testing::Test {
       // If we have a frame, the timestamps should always be monotonically
       // increasing.
       if (frame) {
-        if (last_start_timestamp != kNoTimestamp())
+        if (last_start_timestamp != kNoTimestamp)
           ASSERT_LE(last_start_timestamp, frame->timestamp());
         else
           last_start_timestamp = frame->timestamp();