Change default timestamp to 64 bits in all webrtc directories.

webrtc/base/messagequeue_unittest.cc

Index: webrtc/base/messagequeue_unittest.cc
diff --git a/webrtc/base/messagequeue_unittest.cc b/webrtc/base/messagequeue_unittest.cc
index 78024e0b2d6d6cc270825a9ffbc66e683eb60855..d41e9887bb8507d4ad791bca695d47ed0a56cfb6 100644
--- a/webrtc/base/messagequeue_unittest.cc
+++ b/webrtc/base/messagequeue_unittest.cc
@@ -53,7 +53,7 @@ struct DeletedLockChecker {
 static void DelayedPostsWithIdenticalTimesAreProcessedInFifoOrder(
     MessageQueue* q) {
   EXPECT_TRUE(q != NULL);
-  TimeStamp now = Time();
+  int64_t now = Time();
   q->PostAt(now, NULL, 3);
   q->PostAt(now - 2, NULL, 0);
   q->PostAt(now - 1, NULL, 1);