port to use centralized constants files, and add input validation

Makefile

Index: Makefile
diff --git a/Makefile b/Makefile
index 5d5a6d9c24146991c03ec13971d0458e065e3099..51b26552345be7ae6bf1d5686bc88a14fec70a5a 100644
--- a/Makefile
+++ b/Makefile
@@ -8,7 +8,7 @@ CXXFLAGS=-Wall -Werror -g
 INCLUDE_DIRS=-I../../third_party/chrome/files -I.. $(shell pkg-config --cflags gobject-2.0 dbus-1 dbus-glib-1)
 LIB_DIRS=-L../../third_party/chrome $(shell pkg-config --libs gobject-2.0 dbus-1 dbus-glib-1)
 
-SESSION_COMMON_OBJS=session_manager_service.o child_job.o interface.o constants.o
+SESSION_COMMON_OBJS=session_manager_service.o child_job.o interface.o
 
 DBUS_SOURCE=session_manager.xml
 DBUS_SERVER=bindings/server.h
@@ -18,7 +18,7 @@ SESSION_BIN=session_manager
 SESSION_OBJS=$(SESSION_COMMON_OBJS) session_manager_main.o
 
 SIGNALLER_BIN=signaller
-SIGNALLER_OBJS=signaller.o constants.o
+SIGNALLER_OBJS=signaller.o
 
 TEST_BIN=session_manager_unittest
 TEST_OBJS=$(SESSION_COMMON_OBJS) session_manager_testrunner.o \
@@ -38,19 +38,19 @@ $(SIGNALLER_BIN): $(DBUS_CLIENT) $(SIGNALLER_OBJS)
 
 $(TEST_BIN):	$(TEST_OBJS)
 	$(CXX) $(CXXFLAGS) $(INCLUDE_DIRS) $(LIB_DIRS) $(TEST_OBJS) \
-	 $(LDFLAGS) -lgtest -o $(TEST_BIN)
+	 $(LDFLAGS) -lgtest -lgmock -o $(TEST_BIN)
 
 .cc.o:
 	$(CXX) $(CXXFLAGS) $(INCLUDE_DIRS) -c $< -o $@
 
-bindings_dir:
+$(BINDINGS_DIR):
 	mkdir -p $(BINDINGS_DIR)
 
-$(DBUS_SERVER): $(DBUS_SOURCE) bindings_dir
+$(DBUS_SERVER): $(DBUS_SOURCE) $(BINDINGS_DIR)
 	dbus-binding-tool --mode=glib-server \
 	 --prefix=`basename $(DBUS_SOURCE) .xml` $(DBUS_SOURCE) > $(DBUS_SERVER)
 
-$(DBUS_CLIENT): $(DBUS_SOURCE) bindings_dir
+$(DBUS_CLIENT): $(DBUS_SOURCE) $(BINDINGS_DIR)
 	dbus-binding-tool --mode=glib-client \
 	 --prefix=`basename $(DBUS_SOURCE) .xml` $(DBUS_SOURCE) > $(DBUS_CLIENT)