Add Flag for Enabling 64-bit Legacy DRM Plugins

We are ready for devices to begin migrating to a 64-bit Legacy DRM
Loader. However, not all devices are ready to make this jump yet. A
device needs to have all of its Legacy DRM Plugins ready to run as
64-bit before it can do this. This includes having 64-bit hardware
integrations.

So that devices can turn on 64-bit support as they get ready, I am
adding flags that can be set in a device's device.mk file. There are two
parts:

* ENABLE_MEDIADRM_64 enables building the Legacy DRM Plugin HAL as
  64-bit.

* Setting drm.64bit.enabled=true in PRODUCT_PROPERTY_OVERRIDES switches
  the Legacy DRM Plugin HAL to searching for DRM Plugins in the 64-bit
  directory.

Test: Validated that turning on these flags enables a 64-bit Legacy DRM
      Plugin HAL that loads 64-bit Legacy DRM Plugins from the lib64
      directory.
Bug: 36076017
Change-Id: I8d21fc7e7c0357eb6755839d41caa0f37ca20aff
diff --git a/drm/1.0/default/LegacyPluginPath.cpp b/drm/1.0/default/LegacyPluginPath.cpp
new file mode 100644
index 0000000..369059d
--- /dev/null
+++ b/drm/1.0/default/LegacyPluginPath.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+
+#include "LegacyPluginPath.h"
+
+#include <cutils/properties.h>
+
+namespace android {
+namespace hardware {
+namespace drm {
+namespace V1_0 {
+namespace implementation {
+
+const char* getDrmPluginPath() {
+    if (property_get_bool("drm.64bit.enabled", false)) {
+        return "/vendor/lib64/mediadrm";
+    } else {
+        return "/vendor/lib/mediadrm";
+    }
+}
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace drm
+}  // namespace hardware
+}  // namespace android