Add methods for telling V8 how much memory audio/video is using.

media/filters/audio_renderer_algorithm_unittest.cc

Index: media/filters/audio_renderer_algorithm_unittest.cc
diff --git a/media/filters/audio_renderer_algorithm_unittest.cc b/media/filters/audio_renderer_algorithm_unittest.cc
index e92223cd2bb3b6b45695147b4a7a5fbf86f1e439..986d6b5d8da887d24210c1813bf665ef0fa29f1e 100644
--- a/media/filters/audio_renderer_algorithm_unittest.cc
+++ b/media/filters/audio_renderer_algorithm_unittest.cc
@@ -216,6 +216,9 @@ class AudioRendererAlgorithmTest : public testing::Test {
       FillAlgorithmQueue();
     }
 
+    EXPECT_EQ(algorithm_.frames_buffered() * channels_ * sizeof(float),
+              static_cast<size_t>(algorithm_.GetMemoryUsage()));
+
     int frames_consumed =
         ComputeConsumedFrames(initial_frames_enqueued, initial_frames_buffered);