metricsd: Collect generic stats about the system.

Collect memory usage and disk IO statistics periodically.
Also update the Android.mk file to use clang by default.

BUG: 22953719
TEST: builds on external and internal branches.

Change-Id: I1ee3683d014586cf7f711d2e090a99429752063c
diff --git a/metricsd/Android.mk b/metricsd/Android.mk
index 12dfa18..9620e16 100644
--- a/metricsd/Android.mk
+++ b/metricsd/Android.mk
@@ -84,6 +84,7 @@
 LOCAL_MODULE := libmetrics
 LOCAL_C_INCLUDES := $(metrics_includes)
 LOCAL_CFLAGS := $(metrics_CFLAGS)
+LOCAL_CLANG := true
 LOCAL_CPP_EXTENSION := $(metrics_cpp_extension)
 LOCAL_CPPFLAGS := $(metrics_CPPFLAGS)
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
@@ -97,6 +98,7 @@
 LOCAL_MODULE := metrics_client
 LOCAL_C_INCLUDES := $(metrics_includes)
 LOCAL_CFLAGS := $(metrics_CFLAGS)
+LOCAL_CLANG := true
 LOCAL_CPP_EXTENSION := $(metrics_cpp_extension)
 LOCAL_CPPFLAGS := $(metrics_CPPFLAGS)
 LOCAL_SHARED_LIBRARIES := $(metrics_shared_libraries) \
@@ -133,7 +135,10 @@
   libchromeos-http \
   libchromeos-dbus \
   libcutils \
-  libdbus
+  libdbus \
+  librootdev
+
+LOCAL_CLANG := true
 LOCAL_SRC_FILES := $(metrics_daemon_sources)
 LOCAL_STATIC_LIBRARIES := metrics_daemon_protos
 include $(BUILD_EXECUTABLE)