VideoCaptureAndroid: rewrote the (standalone) implementation of video capture on Android.

Besides being ~40% the size of the previous implementation, this makes it so
that VideoCaptureAndroid can stop and restart capture, which is necessary to
support onPause/onResume reasonably on Android.

BUG=1407
R=henrike@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2334004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4915 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/utility/interface/helpers_android.h b/webrtc/modules/utility/interface/helpers_android.h
new file mode 100644
index 0000000..d0796ec
--- /dev/null
+++ b/webrtc/modules/utility/interface/helpers_android.h
@@ -0,0 +1,34 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_UTILITY_INTERFACE_HELPERS_ANDROID_H_
+#define WEBRTC_MODULES_UTILITY_INTERFACE_HELPERS_ANDROID_H_
+
+#include <jni.h>
+
+namespace webrtc {
+
+// Attach thread to JVM if necessary and detach at scope end if originally
+// attached.
+class AttachThreadScoped {
+ public:
+  explicit AttachThreadScoped(JavaVM* jvm);
+  ~AttachThreadScoped();
+  JNIEnv* env();
+
+ private:
+  bool attached_;
+  JavaVM* jvm_;
+  JNIEnv* env_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_UTILITY_INTERFACE_HELPERS_ANDROID_H_