Bug 4016329 do full string comparisons

Use full string comparisons instead of partial for
  file extension and MIME type.
Do case-insensitive comparison of MIME type and file extensions.
Fix error in comment for String8::getPathExtension.
Remove dead code -- StringTokenizer is unused.

Change-Id: I322be6235abbdaab5f7eafa48926dbb2cf46dc29
diff --git a/drm/drmserver/Android.mk b/drm/drmserver/Android.mk
index 5df2ff8..f94f9a3 100644
--- a/drm/drmserver/Android.mk
+++ b/drm/drmserver/Android.mk
@@ -19,8 +19,7 @@
 LOCAL_SRC_FILES:= \
     main_drmserver.cpp \
     DrmManager.cpp \
-    DrmManagerService.cpp \
-    StringTokenizer.cpp
+    DrmManagerService.cpp
 
 LOCAL_SHARED_LIBRARIES := \
     libutils \