Assume the profile file was created before saving.

bug: 26080105
Change-Id: I9969a4abd8533614922076551fcbae2cdf695525
diff --git a/runtime/utils.cc b/runtime/utils.cc
index ff6b4c0..1e1c7e7 100644
--- a/runtime/utils.cc
+++ b/runtime/utils.cc
@@ -1446,6 +1446,11 @@
   return true;
 }
 
+bool FileExists(const std::string& filename) {
+  struct stat buffer;
+  return stat(filename.c_str(), &buffer) == 0;
+}
+
 std::string PrettyDescriptor(Primitive::Type type) {
   return PrettyDescriptor(Primitive::Descriptor(type));
 }