Android: sync up latest JNI generator changes from downstream.

base/android/jni_generator/sample_for_tests.h

Index: base/android/jni_generator/sample_for_tests.h
diff --git a/base/android/jni_generator/sample_for_tests.h b/base/android/jni_generator/sample_for_tests.h
index 278008b2df769fb4d3edafd2d7e1e12196a8f4fd..4d76408b686b64b0d2dc61e85a0931e0a37d7983 100644
--- a/base/android/jni_generator/sample_for_tests.h
+++ b/base/android/jni_generator/sample_for_tests.h
@@ -6,6 +6,7 @@
 #include <map>
 #include <string>
 
+#include "base/android/jni_android.h"
 #include "base/basictypes.h"
 
 namespace base {
@@ -36,6 +37,9 @@ class CPPClass {
 
   void IterateAndDoSomethingWithStructB(JNIEnv* env, jobject obj);
 
+  base::android::ScopedJavaLocalRef<jstring> ReturnAString(
+      JNIEnv* env, jobject obj);
+
  private:
   std::map<long, std::string> map_;