[Chromecast] Avoid crashing if the AudioProvider returns 0 frames

Change-Id: If7c10365ff4b69c543150cd51dd74a50662bac07
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2042325Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739190}

chromecast/media/audio/audio_clock_simulator.cc

@@ -152,6 +152,10 @@ AudioClockSimulator::FillResult AudioClockSimulator::FillDataLengthen(
   }
   int64_t timestamp = playout_timestamp + FramesToMicroseconds(offset);
   int provided = provider_->FillFrames(desired_fill, timestamp, channels);
+  if (provided == 0) {
+    return {false, 0};
+  }
+
   input_frames_ += provided;
   InterpolateLonger(provided, channel_data, offset);