base: Add ScopedJavaLocalFrame class.

mojo/services/native_viewport/native_viewport_android.cc

Index: mojo/services/native_viewport/native_viewport_android.cc
diff --git a/mojo/services/native_viewport/native_viewport_android.cc b/mojo/services/native_viewport/native_viewport_android.cc
index 55b88c9f514ed53390c639a6cef94a59b22e9d6c..9eb80835479297a466f67e0762dec36b0fee0357 100644
--- a/mojo/services/native_viewport/native_viewport_android.cc
+++ b/mojo/services/native_viewport/native_viewport_android.cc
@@ -60,7 +60,13 @@ void NativeViewportAndroid::SurfaceCreated(JNIEnv* env,
                                            jobject obj,
                                            jobject jsurface) {
   base::android::ScopedJavaLocalRef<jobject> protector(env, jsurface);
-  window_ = ANativeWindow_fromSurface(env, jsurface);
+  // Note: This ensures that any local references used by
+  // ANativeWindow_fromSurface are released immediately. This is needed as a
+  // workaround for https://code.google.com/p/android/issues/detail?id=68174
+  {
+    base::android::ScopedJavaLocalFrame scoped_local_reference_frame(env);
+    window_ = ANativeWindow_fromSurface(env, jsurface);
+  }
   delegate_->OnAcceleratedWidgetAvailable(window_);
 }