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/CryptoFactory.cpp b/drm/1.0/default/CryptoFactory.cpp
index e46233d..935786d 100644
--- a/drm/1.0/default/CryptoFactory.cpp
+++ b/drm/1.0/default/CryptoFactory.cpp
@@ -17,6 +17,7 @@
 
 #include "CryptoFactory.h"
 #include "CryptoPlugin.h"
+#include "LegacyPluginPath.h"
 #include "TypeConvert.h"
 #include <utils/Log.h>
 
@@ -27,7 +28,7 @@
 namespace implementation {
 
     CryptoFactory::CryptoFactory() :
-        loader("/vendor/lib/mediadrm", "createCryptoFactory") {
+        loader(getDrmPluginPath(), "createCryptoFactory") {
     }
 
     // Methods from ::android::hardware::drm::V1_0::ICryptoFactory follow.