Update Android.mk to include new files.

Change-Id: Id543ee7d2a65b65c868554a17f593c0a4958e873

jni/Android.mk

diff --git a/jni/Android.mk b/jni/Android.mk
index 30b489e..84d105e 100644
--- a/jni/Android.mk
+++ b/jni/Android.mk
@@ -146,9 +146,11 @@
                    $(CERES_SRC_PATH)/dynamic_compressed_row_sparse_matrix.cc \
                    $(CERES_SRC_PATH)/evaluator.cc \
                    $(CERES_SRC_PATH)/file.cc \
+                   $(CERES_SRC_PATH)/gradient_checker.cc \
                    $(CERES_SRC_PATH)/gradient_checking_cost_function.cc \
                    $(CERES_SRC_PATH)/gradient_problem.cc \
                    $(CERES_SRC_PATH)/gradient_problem_solver.cc \
+		   $(CERES_SRC_PATH)/is_close.cc \
                    $(CERES_SRC_PATH)/implicit_schur_complement.cc \
                    $(CERES_SRC_PATH)/iterative_schur_complement_solver.cc \
                    $(CERES_SRC_PATH)/lapack.cc \