Make FileStat have millisecond precisions, for linux, mac and android.

runtime/bin/file_macos.cc

Index: runtime/bin/file_macos.cc
diff --git a/runtime/bin/file_macos.cc b/runtime/bin/file_macos.cc
index b5a1dd009d628dfc9e4c853c3f886661b9153037..9b0b2ada0db3f5ddd445f0d380fc6acd4951ff96 100644
--- a/runtime/bin/file_macos.cc
+++ b/runtime/bin/file_macos.cc
@@ -250,6 +250,12 @@ int64_t File::LengthFromPath(const char* name) {
 }
 
 
+static int64_t TimespecToMilliseconds(const struct timespec& t) {
+  return static_cast<int64_t>(t.tv_sec) * 1000L +
+      static_cast<int64_t>(t.tv_nsec) / 1000000L;
+}
+
+
 void File::Stat(const char* name, int64_t* data) {
   struct stat st;
   if (NO_RETRY_EXPECTED(stat(name, &st)) == 0) {
@@ -265,6 +271,9 @@ void File::Stat(const char* name, int64_t* data) {
     data[kCreatedTime] = st.st_ctime;
     data[kModifiedTime] = st.st_mtime;
     data[kAccessedTime] = st.st_atime;
+    data[kCreatedTime] = TimespecToMilliseconds(st.st_ctimespec);
+    data[kModifiedTime] = TimespecToMilliseconds(st.st_mtimespec);
+    data[kAccessedTime] = TimespecToMilliseconds(st.st_atimespec);
     data[kMode] = st.st_mode;
     data[kSize] = st.st_size;
   } else {