Change default timestamp to 64 bits in all webrtc directories.

webrtc/base/fileutils.cc

Index: webrtc/base/fileutils.cc
diff --git a/webrtc/base/fileutils.cc b/webrtc/base/fileutils.cc
index cb23153de779328c3cf3391a0df87aed6ddaa283..d354dd8eb56d4ce79dda47b224ab1e5e603849d6 100644
--- a/webrtc/base/fileutils.cc
+++ b/webrtc/base/fileutils.cc
@@ -133,7 +133,7 @@ bool DirectoryIterator::OlderThan(int seconds) const {
 #else
   file_modify_time = stat_.st_mtime;
 #endif
-  return TimeDiff(time(NULL), file_modify_time) >= seconds;
+  return time(NULL) - file_modify_time >= seconds;
 }
 
 FilesystemInterface* Filesystem::default_filesystem_ = NULL;