[Chromecast] Fix crash when stream is paused

Bug: internal b/143559499
Change-Id: I57244b6fb772f15ffb4c9f31c4194a2f98d55801
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894263
Commit-Queue: Kenneth MacKay <kmackay@chromium.org>
Commit-Queue: Yuchen Liu <yucliu@chromium.org>
Auto-Submit: Kenneth MacKay <kmackay@chromium.org>
Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#711466}

chromecast/media/cma/backend/mixer/mixer_input_connection.cc

@@ -225,7 +225,9 @@ MixerInputConnection::~MixerInputConnection() {
 bool MixerInputConnection::HandleMetadata(
     const mixer_service::Generic& message) {
   DCHECK(io_task_runner_->RunsTasksInCurrentSequence());
+  if (inactivity_timer_.IsRunning()) {
     inactivity_timer_.Reset();
+  }
 
   if (message.has_set_start_timestamp()) {
     RestartPlaybackAt(message.set_start_timestamp().start_timestamp(),
@@ -247,7 +249,9 @@ bool MixerInputConnection::HandleAudioData(char* data,
                                            int size,
                                            int64_t timestamp) {
   DCHECK(io_task_runner_->RunsTasksInCurrentSequence());
+  if (inactivity_timer_.IsRunning()) {
     inactivity_timer_.Reset();
+  }
 
   const int frame_size =
       num_channels_ * mixer_service::GetSampleSizeBytes(sample_format_);
@@ -312,7 +316,9 @@ bool MixerInputConnection::HandleAudioBuffer(
     int size,
     int64_t timestamp) {
   DCHECK(io_task_runner_->RunsTasksInCurrentSequence());
+  if (inactivity_timer_.IsRunning()) {
     inactivity_timer_.Reset();
+  }
 
   DCHECK_EQ(data - buffer->data(), kAudioMessageHeaderSize);
   DCHECK_EQ(sample_format_, mixer_service::SAMPLE_FORMAT_FLOAT_P);