transcoder: initial version of pause/resume

- Add pause/resume in TranscoderWrapper, save paused state on pause
  and use it to create new transcoder on resume.

Misc fixes:

- TranscoderWrapper::stop should only cancel transcoder if the stop
  is for the currently running job. Scheduler could call stop to
  cancel a job any time.
- Don't hold TranscoderWrapper lock when running event runnable. If
  the runnable calls back into scheduler, and scheduler may call
  transcoder again and deadlock.
- Don't report abort as error if the transcoder is cancelled explicitly.
- Push decoder/encoder start as msgs, so that they could be skipped too
  if the job is cancelled shortly after starts.

Tests:
Add tests for cancel/pause/resume with real transcoder.

bug: 154734285
bug: 154733948
test: unit testing
Change-Id: I2b7d3da69df53b92ab351db455310799ba0e0e8f
diff --git a/media/libmediatranscoding/transcoder/tests/MediaTranscoderTests.cpp b/media/libmediatranscoding/transcoder/tests/MediaTranscoderTests.cpp
index 67f1ca1..330261c 100644
--- a/media/libmediatranscoding/transcoder/tests/MediaTranscoderTests.cpp
+++ b/media/libmediatranscoding/transcoder/tests/MediaTranscoderTests.cpp
@@ -20,6 +20,7 @@
 #define LOG_TAG "MediaTranscoderTests"
 
 #include <android-base/logging.h>
+#include <fcntl.h>
 #include <gtest/gtest.h>
 #include <media/MediaSampleReaderNDK.h>
 #include <media/MediaTranscoder.h>
@@ -74,7 +75,7 @@
                                   int32_t progress __unused) override {}
 
     virtual void onCodecResourceLost(const MediaTranscoder* transcoder __unused,
-                                     const std::shared_ptr<const Parcelable>& pausedState
+                                     const std::shared_ptr<const Parcel>& pausedState
                                              __unused) override {}
 
     void waitForTranscodingFinished() {