Call java SurfaceTextureHelper.dispose from the corresponding C++ destructor.

This makes it clearer that the C++ SurfaceTextureHelper owns its associated java object it.

In addition, arrange so that the SurfaceTextureHelper.stopListening
method (in java) can be called from any thread.

BUG=

Review-Url: https://codereview.webrtc.org/1988043002
Cr-Commit-Position: refs/heads/master@{#12941}

webrtc/api/java/android/org/webrtc/SurfaceTextureHelper.java

@@ -63,7 +63,7 @@ class SurfaceTextureHelper {
     // http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/5.1.1_r1/android/graphics/SurfaceTexture.java#195.
     // Therefore, in order to control the callback thread on API lvl < 21, the SurfaceTextureHelper
     // is constructed on the |handler| thread.
-    return ThreadUtils.invokeUninterruptibly(handler, new Callable<SurfaceTextureHelper>() {
+    return ThreadUtils.invokeAtFrontUninterruptibly(handler, new Callable<SurfaceTextureHelper>() {
       @Override
       public SurfaceTextureHelper call() {
         try {
@@ -373,17 +373,18 @@ class SurfaceTextureHelper {
 
   /**
    * Stop listening. The listener set in startListening() is guaranteded to not receive any more
-   * onTextureFrameAvailable() callbacks after this function returns. This function must be called
-   * on the getHandler() thread.
+   * onTextureFrameAvailable() callbacks after this function returns.
    */
   public void stopListening() {
-    if (handler.getLooper().getThread() != Thread.currentThread()) {
-      throw new IllegalStateException("Wrong thread.");
-    }
     Logging.d(TAG, "stopListening()");
     handler.removeCallbacks(setListenerRunnable);
-    this.listener = null;
-    this.pendingListener = null;
+    ThreadUtils.invokeAtFrontUninterruptibly(handler, new Runnable() {
+      @Override
+      public void run() {
+        listener = null;
+        pendingListener = null;
+      }
+    });
   }
 
   /**
@@ -431,24 +432,15 @@ class SurfaceTextureHelper {
    */
   public void dispose() {
     Logging.d(TAG, "dispose()");
-    if (handler.getLooper().getThread() == Thread.currentThread()) {
-      isQuitting = true;
-      if (!isTextureInUse) {
-        release();
-      }
-      return;
-    }
-    final CountDownLatch barrier = new CountDownLatch(1);
-    handler.postAtFrontOfQueue(new Runnable() {
-      @Override public void run() {
+    ThreadUtils.invokeAtFrontUninterruptibly(handler, new Runnable() {
+      @Override
+      public void run() {
         isQuitting = true;
-        barrier.countDown();
         if (!isTextureInUse) {
           release();
         }
       }
     });
-    ThreadUtils.awaitUninterruptibly(barrier);
   }
 
   public void textureToYUV(ByteBuffer buf,

webrtc/api/java/jni/androidvideocapturer_jni.cc

@@ -53,13 +53,6 @@ AndroidVideoCapturerJni::~AndroidVideoCapturerJni() {
       *j_video_capturer_,
       GetMethodID(jni(), *j_video_capturer_class_, "dispose", "()V"));
   CHECK_EXCEPTION(jni()) << "error during VideoCapturer.dispose()";
-  if (surface_texture_helper_) {
-    jni()->CallVoidMethod(
-        surface_texture_helper_->GetJavaSurfaceTextureHelper(),
-        GetMethodID(jni(), FindClass(jni(), "org/webrtc/SurfaceTextureHelper"),
-                    "dispose", "()V"));
-  }
-  CHECK_EXCEPTION(jni()) << "error during SurfaceTextureHelper.dispose()";
 }
 
 void AndroidVideoCapturerJni::Start(int width, int height, int framerate,

webrtc/api/java/jni/surfacetexturehelper_jni.cc

@@ -14,6 +14,7 @@
 #include "webrtc/api/java/jni/classreferenceholder.h"
 #include "webrtc/base/bind.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
 
 namespace webrtc_jni {
 
@@ -48,6 +49,14 @@ SurfaceTextureHelper::SurfaceTextureHelper(JNIEnv* jni,
 }
 
 SurfaceTextureHelper::~SurfaceTextureHelper() {
+  LOG(LS_INFO) << "SurfaceTextureHelper dtor";
+  JNIEnv* jni = AttachCurrentThreadIfNeeded();
+  jni->CallVoidMethod(
+      *j_surface_texture_helper_,
+      GetMethodID(jni, FindClass(jni, "org/webrtc/SurfaceTextureHelper"),
+                  "dispose", "()V"));
+
+  CHECK_EXCEPTION(jni) << "error during SurfaceTextureHelper.dispose()";
 }
 
 jobject SurfaceTextureHelper::GetJavaSurfaceTextureHelper() const {

webrtc/api/java/jni/surfacetexturehelper_jni.h

@@ -30,6 +30,8 @@ namespace webrtc_jni {
 // SurfaceTextureHelper is reference counted to make sure that it is not
 // destroyed while a VideoFrameBuffer is in use.
 // This class is the C++ counterpart of the java class SurfaceTextureHelper.
+// It owns the corresponding java object, and calls the java dispose
+// method when destroyed.
 // Usage:
 // 1. Create an instance of this class.
 // 2. Get the Java SurfaceTextureHelper with GetJavaSurfaceTextureHelper().

webrtc/api/java/src/org/webrtc/MediaCodecVideoDecoder.java

@@ -547,10 +547,10 @@ public class MediaCodecVideoDecoder {
     }
 
     public void release() {
-      // SurfaceTextureHelper.dispose() will block until any onTextureFrameAvailable() in
-      // progress is done. Therefore, the call to dispose() must be outside any synchronized
+      // SurfaceTextureHelper.stopListening() will block until any onTextureFrameAvailable() in
+      // progress is done. Therefore, the call must be outside any synchronized
       // statement that is also used in the onTextureFrameAvailable() above to avoid deadlocks.
-      surfaceTextureHelper.dispose();
+      surfaceTextureHelper.stopListening();
       synchronized (newFrameLock) {
         if (renderedBuffer != null) {
           surfaceTextureHelper.returnTextureFrame();