Upstream Android JNI code, allowing us to use more ScopedJava references.

base/android/jni_string.h

Index: base/android/jni_string.h
diff --git a/base/android/jni_string.h b/base/android/jni_string.h
index bb902d1884f66b9c2941ecd569ff789900b7e77a..2b013eadfc39a018f4d4728511793718c11e0904 100644
--- a/base/android/jni_string.h
+++ b/base/android/jni_string.h
@@ -8,6 +8,7 @@
 #include <jni.h>
 #include <string>
 
+#include "base/android/scoped_java_ref.h"
 #include "base/string16.h"
 #include "base/string_piece.h"
 
@@ -16,15 +17,19 @@ namespace android {
 
 // Convert a Java string to UTF8. Returns a std string.
 std::string ConvertJavaStringToUTF8(JNIEnv* env, jstring str);
+std::string ConvertJavaStringToUTF8(const JavaRef<jstring>& str);
 
 // Convert a std string to Java string.
-jstring ConvertUTF8ToJavaString(JNIEnv* env, const base::StringPiece& str);
+ScopedJavaLocalRef<jstring> ConvertUTF8ToJavaString(
+    JNIEnv* env, const base::StringPiece& str);
 
 // Convert a Java string to UTF16. Returns a string16.
 string16 ConvertJavaStringToUTF16(JNIEnv* env, jstring str);
+string16 ConvertJavaStringToUTF16(const JavaRef<jstring>& str);
 
 // Convert a string16 to a Java string.
-jstring ConvertUTF16ToJavaString(JNIEnv* env, const string16& str);
+ScopedJavaLocalRef<jstring> ConvertUTF16ToJavaString(
+    JNIEnv* env, const string16& str);
 
 }  // namespace android
 }  // namespace base