[AIDL CTS] Fix visualizer cts issue with AIDL effects

1. Mapping VISUALIZER_CMD_CAPTURE command correctly with handler
2. Capture silent data when inactive Visualizer receive capture command

Bug: 270155119
Test: enable aidl and
atest CtsMediaAudioTestCases:android.media.audio.cts.VisualizerTest

Change-Id: Ic37e4c7e0b66af662381a187064974d56e5cc48e
diff --git a/media/libeffects/visualizer/aidl/VisualizerContext.h b/media/libeffects/visualizer/aidl/VisualizerContext.h
index 3cb711e..958035f 100644
--- a/media/libeffects/visualizer/aidl/VisualizerContext.h
+++ b/media/libeffects/visualizer/aidl/VisualizerContext.h
@@ -83,7 +83,7 @@
     uint32_t mLastCaptureIdx GUARDED_BY(mMutex) = 0;
     Visualizer::ScalingMode mScalingMode GUARDED_BY(mMutex) = Visualizer::ScalingMode::NORMALIZED;
     struct timespec mBufferUpdateTime GUARDED_BY(mMutex);
-    // capture buf with 8 bits PCM
+    // capture buf with 8 bits mono PCM samples
     std::array<uint8_t, kMaxCaptureBufSize> mCaptureBuf GUARDED_BY(mMutex);
     uint32_t mDownstreamLatency GUARDED_BY(mMutex) = 0;
     uint32_t mCaptureSamples GUARDED_BY(mMutex) = kMaxCaptureBufSize;