aaudio: fix timestamps and underruns

Start the client after we get valid timing data from the server.
That can take a while because of the long cold start times.
The client is synced with the current position of the service.
Now the client can start clean with no underruns.

Bug: 63918065
Test: test_timestamps.cpp
Change-Id: I5d01eb844e4b14cd5477d56ea1dd9e309abc1c52
diff --git a/services/oboeservice/AAudioServiceStreamMMAP.h b/services/oboeservice/AAudioServiceStreamMMAP.h
index bf0aab3..83cd2ef 100644
--- a/services/oboeservice/AAudioServiceStreamMMAP.h
+++ b/services/oboeservice/AAudioServiceStreamMMAP.h
@@ -53,14 +53,6 @@
     aaudio_result_t open(const aaudio::AAudioStreamRequest &request) override;
 
     /**
-     * Start the flow of audio data.
-     *
-     * This is not guaranteed to be synchronous but it currently is.
-     * An AAUDIO_SERVICE_EVENT_STARTED will be sent to the client when complete.
-     */
-    aaudio_result_t start() override;
-
-    /**
      * Stop the flow of data so that start() can resume without loss of data.
      *
      * This is not guaranteed to be synchronous but it currently is.
@@ -89,6 +81,12 @@
 
     aaudio_result_t getHardwareTimestamp(int64_t *positionFrames, int64_t *timeNanos) override;
 
+    /**
+     * Device specific startup.
+     * @return AAUDIO_OK or negative error.
+     */
+    aaudio_result_t startDevice() override;
+
 private:
 
     bool                     mInService = false;