Use String8/16 c_str

Bug: 295394788
Test: make checkbuild
Change-Id: I538720d4de2dcc038b417048209782ff605b7e30
diff --git a/media/jni/android_media_MediaDrm.cpp b/media/jni/android_media_MediaDrm.cpp
index b70818d..c616b84f 100644
--- a/media/jni/android_media_MediaDrm.cpp
+++ b/media/jni/android_media_MediaDrm.cpp
@@ -708,8 +708,8 @@
     jclass clazz = gFields.hashmapClassId;
     jobject hashMap = env->NewObject(clazz, gFields.hashmap.init);
     for (size_t i = 0; i < map.size(); ++i) {
-        jstring jkey = env->NewStringUTF(map.keyAt(i).string());
-        jstring jvalue = env->NewStringUTF(map.valueAt(i).string());
+        jstring jkey = env->NewStringUTF(map.keyAt(i).c_str());
+        jstring jvalue = env->NewStringUTF(map.valueAt(i).c_str());
         env->CallObjectMethod(hashMap, gFields.hashmap.put, jkey, jvalue);
         env->DeleteLocalRef(jkey);
         env->DeleteLocalRef(jvalue);
@@ -1169,7 +1169,7 @@
         jbyteArray jrequest = VectorToJByteArray(env, request);
         env->SetObjectField(keyObj, gFields.keyRequest.data, jrequest);
 
-        jstring jdefaultUrl = env->NewStringUTF(defaultUrl.string());
+        jstring jdefaultUrl = env->NewStringUTF(defaultUrl.c_str());
         env->SetObjectField(keyObj, gFields.keyRequest.defaultUrl, jdefaultUrl);
 
         switch (keyRequestType) {
@@ -1332,7 +1332,7 @@
         jbyteArray jrequest = VectorToJByteArray(env, request);
         env->SetObjectField(provisionObj, gFields.provisionRequest.data, jrequest);
 
-        jstring jdefaultUrl = env->NewStringUTF(defaultUrl.string());
+        jstring jdefaultUrl = env->NewStringUTF(defaultUrl.c_str());
         env->SetObjectField(provisionObj, gFields.provisionRequest.defaultUrl, jdefaultUrl);
     }
 
@@ -1686,7 +1686,7 @@
         return NULL;
     }
 
-    return env->NewStringUTF(value.string());
+    return env->NewStringUTF(value.c_str());
 }
 
 static jbyteArray android_media_MediaDrm_getPropertyByteArray(