Support code coverage with Jack

Building an app with Jack and with the environment variable
EMMA_INSTRUMENT_STATIC set to true will apply code coverage
onto the app targeting Jacoco.

Bug: 20115492
Change-Id: Ief3640fa3faa466f7f6aaa9739e06d3db24110a0
diff --git a/core/proguard.jacoco.flags b/core/proguard.jacoco.flags
new file mode 100644
index 0000000..c3bed94
--- /dev/null
+++ b/core/proguard.jacoco.flags
@@ -0,0 +1,8 @@
+# Keep everything for the emma classes
+-keep class com.vladium.** {
+  *;
+}
+# Keep everything for the jacoco classes
+-keep class org.jacoco.** {
+  *;
+}