Remove dependency to libmediadrm from drm HAL

drm HAL has been using libmediadrm for android::SharedLibrary class and
android::PluginLoader class. This is a Treble violation since
libmediadrm is a framework-only library that is not available to
vendors.

To solve the problem, the two classes are copied into this directory
to form a small static library android.hardware.drm@1.0-helper.a.

Bug: 38302533
Test: mm under /hardware/interfaces/drm/1.0/default and
/hardware/interfaces/drm/1.0/vts/functional

Change-Id: I7b4e5cdb3bc815e971e0c3b7ec99ea86042e13eb
diff --git a/drm/1.0/default/Android.mk b/drm/1.0/default/Android.mk
index 4c05da8..0cc6e71 100644
--- a/drm/1.0/default/Android.mk
+++ b/drm/1.0/default/Android.mk
@@ -36,6 +36,9 @@
   libutils \
   libbinder \
 
+LOCAL_STATIC_LIBRARIES := \
+  android.hardware.drm@1.0-helper \
+
 LOCAL_C_INCLUDES := \
   hardware/interfaces/drm
 
@@ -71,10 +74,12 @@
     libhidlmemory \
     libhidltransport \
     liblog \
-    libmediadrm \
     libstagefright_foundation \
     libutils \
 
+LOCAL_STATIC_LIBRARIES := \
+    android.hardware.drm@1.0-helper \
+
 LOCAL_C_INCLUDES := \
     frameworks/native/include \
     frameworks/av/include