VideoCapturerAndroid: Report onFirstFrameAvailable() for textures as well

We currently only trigger onFirstFrameAvailable() for byte buffer frames.

R=perkj@webrtc.org

Review URL: https://codereview.webrtc.org/1701993002 .

Cr-Commit-Position: refs/heads/master@{#11670}

webrtc/api/java/android/org/webrtc/VideoCapturerAndroid.java

@@ -678,9 +678,13 @@ public class VideoCapturerAndroid implements
       return;
     }
     if (dropNextFrame)  {
-     surfaceHelper.returnTextureFrame();
-     dropNextFrame = false;
-     return;
+      surfaceHelper.returnTextureFrame();
+      dropNextFrame = false;
+      return;
+    }
+    if (eventsHandler != null && !firstFrameReported) {
+      eventsHandler.onFirstFrameAvailable();
+      firstFrameReported = true;
     }
 
     int rotation = getFrameOrientation();