Pass application packagename to drm plugin.

Pass application package name to createPlugin and createDrmPlugin.
The application packagename will be used as part of a unique
identifier for drm plugin.

Test: Play Movies.

Test: ANDROID_BUILD_TOP= ./android-gts/tools/gts-tradefed run gts -m
GtsMediaTestCases --test
com.google.android.media.gts.WidevineH264PlaybackTests#testL1With480P60

Verify the application's packagename is reachable in the drm plugin's
debug log.

bug: 27101531

Change-Id: I84fb09b591a7af63f6e20004e910112a4ce6ebac
diff --git a/drm/libmediadrm/Drm.cpp b/drm/libmediadrm/Drm.cpp
index 07e9414..e3176e3 100644
--- a/drm/libmediadrm/Drm.cpp
+++ b/drm/libmediadrm/Drm.cpp
@@ -303,7 +303,8 @@
     return true;
 }
 
-status_t Drm::createPlugin(const uint8_t uuid[16]) {
+status_t Drm::createPlugin(const uint8_t uuid[16],
+                           const String8& /* appPackageName */) {
     Mutex::Autolock autoLock(mLock);
 
     if (mPlugin != NULL) {
@@ -319,7 +320,12 @@
     }
 
     status_t result = mFactory->createDrmPlugin(uuid, &mPlugin);
-    mPlugin->setListener(this);
+    if (mPlugin) {
+        mPlugin->setListener(this);
+    } else {
+        ALOGE("Failed to create plugin");
+        return UNEXPECTED_NULL;
+    }
     return result;
 }