DrmUtils: refactor IDrm/ICrypto creation

Added utilities to:
* Query config for IMediaDrmService usage
* Create remote vs local IDrm/ICrypto object based on aforementioned config

Bug: 134787536
Test: MediaDrmClearkeyTest#testClearKeyPlaybackCenc
Change-Id: I72df528c0bbd8a6dbd3c4962ac91eb89696bcaf7
diff --git a/drm/libmediadrm/DrmUtils.cpp b/drm/libmediadrm/DrmUtils.cpp
new file mode 100644
index 0000000..7cc1697
--- /dev/null
+++ b/drm/libmediadrm/DrmUtils.cpp
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "DrmUtils"
+
+#include <utils/String16.h>
+#include <binder/IInterface.h>
+#include <binder/IServiceManager.h>
+#include <cutils/properties.h>
+
+#include <mediadrm/CryptoHal.h>
+#include <mediadrm/DrmHal.h>
+#include <mediadrm/DrmUtils.h>
+#include <mediadrm/ICrypto.h>
+#include <mediadrm/IDrm.h>
+#include <mediadrm/IMediaDrmService.h>
+
+namespace android {
+namespace DrmUtils {
+
+namespace {
+template<typename Iface>
+sp<Iface> MakeObjectWithService(status_t *pstatus) {
+    status_t err = OK;
+    status_t &status = pstatus ? *pstatus : err;
+    sp<IServiceManager> sm = defaultServiceManager();
+    sp<IBinder> binder = sm->getService(String16("media.drm"));
+
+    sp<IMediaDrmService> service = interface_cast<IMediaDrmService>(binder);
+    if (service == NULL) {
+        status = UNKNOWN_ERROR;
+        return NULL;
+    }
+
+    auto obj = service->makeObject<Iface>();
+    if (obj == NULL) {
+        status = UNKNOWN_ERROR;
+        return NULL;
+    }
+
+    status = obj->initCheck();
+    if (status != OK && status != NO_INIT) {
+        return NULL;
+    }
+    return obj;
+}
+
+template<typename Iface, typename Hal>
+sp<Iface> MakeObject(status_t *pstatus) {
+    if (UseDrmService()) {
+        return MakeObjectWithService<Iface>(pstatus);
+    } else {
+        return new Hal();
+    }
+}
+} // namespace
+
+bool UseDrmService() {
+    return property_get_bool("persist.device_config.media_native.mediadrmserver", true);
+}
+
+sp<IDrm> MakeDrm(status_t *pstatus) {
+    return MakeObject<IDrm, DrmHal>(pstatus);
+}
+
+sp<ICrypto> MakeCrypto(status_t *pstatus) {
+    return MakeObject<ICrypto, CryptoHal>(pstatus);
+}
+
+}  // namespace DrmUtils
+}  // namespace android