Use Jsmn to parse json data

[ Merge of http://go/wvgerrit/16628 ]

Jsmn will replace a local method that parsed json init data.
Added a fix to include all key Ids in the WidevineCencHeader rather than
just the first. Also modified the content_id to reflect that it is a
base64 encoded value.

b/20630275

Change-Id: I7080c8cea21be4dea09a4905a96b4cc03e584c1d

libwvdrmengine/cdm/test/unit-test.mk

@@ -34,12 +34,13 @@ LOCAL_C_INCLUDES += external/protobuf/src
 LOCAL_STATIC_LIBRARIES := \
     libcdm \
     libcdm_protos \
+    libcdm_utils \
     libcrypto_static \
-    libwvgmock \
+    libjsmn \
     libgtest \
     libgtest_main \
+    libwvgmock \
     libwvlevel3 \
-    libcdm_utils \
 
 LOCAL_SHARED_LIBRARIES := \
     libcutils \