Add test cases about sync feature.

MyTracks/proguard-google-api-client.txt

@@ -0,0 +1,25 @@
+# ProGuard Configuration file
+#
+# See http://proguard.sourceforge.net/index.html#manual/usage.html
+
+# Needed to keep generic types and @Key annotations accessed via reflection
+
+-keepattributes Signature,RuntimeVisibleAnnotations,AnnotationDefault
+
+-keepclassmembers class * {
+  @com.google.api.client.util.Key <fields>;
+}
+
+# Needed by Guava
+# See https://groups.google.com/forum/#!topic/guava-discuss/YCZzeCiIVoI
+
+-dontwarn sun.misc.Unsafe
+-dontwarn com.google.common.collect.MinMaxPriorityQueue
+
+# Needed by google-http-client-android when linking against an older platform version
+
+-dontwarn com.google.api.client.extensions.android.**
+
+# Needed by google-api-client-android when linking against an older platform version
+
+-dontwarn com.google.api.client.googleapis.extensions.android.**