Start transition the metrics library to non-static API. Use gmock in tests.

Review URL: http://codereview.chromium.org/2049007
diff --git a/metrics/Makefile b/metrics/Makefile
index cb85fb9..16e1d9f 100644
--- a/metrics/Makefile
+++ b/metrics/Makefile
@@ -28,7 +28,7 @@
 	metrics_daemon_test.o
 
 DAEMON_LDFLAGS = $(LDCONFIG) -lrt -lbase -lpthread -lgflags
-TESTDAEMON_LIBS = -lgtest
+TESTDAEMON_LIBS = -lgmock -lgtest
 
 all: $(LIB) $(SHAREDLIB) $(CLIENT) $(DAEMON)