Use the exact-width integer types defined in <stdint.h> rather than

net/base/backoff_entry.h

Index: net/base/backoff_entry.h
diff --git a/net/base/backoff_entry.h b/net/base/backoff_entry.h
index be9d510474e9bd7bb0988b114ebee4cb93f6fad8..2aa3a96aca8de51ea95442abe0d69d1aa372e8e8 100644
--- a/net/base/backoff_entry.h
+++ b/net/base/backoff_entry.h
@@ -45,11 +45,11 @@ class NET_EXPORT BackoffEntry : NON_EXPORTED_BASE(public base::NonThreadSafe) {
 
     // Maximum amount of time we are willing to delay our request, -1
     // for no maximum.
-    int64 maximum_backoff_ms;
+    int64_t maximum_backoff_ms;
 
     // Time to keep an entry from being discarded even when it
     // has no significant state, -1 to never discard.
-    int64 entry_lifetime_ms;
+    int64_t entry_lifetime_ms;
 
     // If true, we always use a delay of initial_delay_ms, even before
     // we've seen num_errors_to_ignore errors.  Otherwise, initial_delay_ms