Revert "SoundPool: Use caller thread for sound playback"

This reverts commit 66262b16fb.

Reason for revert: < CL will be reverted since we are seeing a memory  regression. Please refer this bug http://b/145834064. Exempt-From-Owner-Approval: see go/perf-revert-firs>

Change-Id: I42db74b5e65f6cdc88d69bfbb686c93620ee563c

media/jni/soundpool/StreamManager.cpp

@@ -38,7 +38,7 @@ static constexpr bool kStealActiveStream_OldestFirst = true;
 // kPlayOnCallingThread = true prior to R.
 // Changing to false means calls to play() are almost instantaneous instead of taking around
 // ~10ms to launch the AudioTrack. It is perhaps 100x faster.
-static constexpr bool kPlayOnCallingThread = true;
+static constexpr bool kPlayOnCallingThread = false;
 
 // Amount of time for a StreamManager thread to wait before closing.
 static constexpr int64_t kWaitTimeBeforeCloseNs = 9 * NANOS_PER_SECOND;
@@ -167,7 +167,6 @@ int32_t StreamManager::queueForPlay(const std::shared_ptr<Sound> &sound,
                 if (!stream->getPairStream()->hasSound()) {
                     if (stream->getSoundID() == soundID) {
                         newStream = stream;
-                        fromAvailableQueue = false;
                         break;
                     } else if (newStream == nullptr) {
                         newStream = stream;