Android: Make classes non-final

The classes are not mockable if they are final.

R=phoglund@webrtc.org

Review URL: https://codereview.webrtc.org/1459873002 .

Cr-Commit-Position: refs/heads/master@{#10714}

talk/app/webrtc/java/android/org/webrtc/EglBase.java

@@ -44,7 +44,7 @@ import javax.microedition.khronos.egl.EGLSurface;
 /**
  * Holds EGL state and utility methods for handling an EGLContext, an EGLDisplay, and an EGLSurface.
  */
-public final class EglBase {
+public class EglBase {
   private static final String TAG = "EglBase";
   // These constants are taken from EGL14.EGL_OPENGL_ES2_BIT and EGL14.EGL_CONTEXT_CLIENT_VERSION.
   // https://android.googlesource.com/platform/frameworks/base/+/master/opengl/java/android/opengl/EGL14.java

talk/app/webrtc/java/android/org/webrtc/SurfaceTextureHelper.java

@@ -51,7 +51,7 @@ import javax.microedition.khronos.egl.EGLContext;
  * wrapping texture frames into webrtc::VideoFrames and also handles calling returnTextureFrame()
  * when the webrtc::VideoFrame is no longer used.
  */
-final class SurfaceTextureHelper {
+class SurfaceTextureHelper {
   private static final String TAG = "SurfaceTextureHelper";
   /**
    * Callback interface for being notified that a new texture frame is available. The calls will be