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

net/cert/signed_tree_head.h

Index: net/cert/signed_tree_head.h
diff --git a/net/cert/signed_tree_head.h b/net/cert/signed_tree_head.h
index fdeef4aae50bbf14c2672491a2290f00e166f61c..fdbcdc48499c4f439cac0471ffe32be81fe41295 100644
--- a/net/cert/signed_tree_head.h
+++ b/net/cert/signed_tree_head.h
@@ -17,7 +17,7 @@ namespace net {
 
 namespace ct {
 
-static const uint8 kSthRootHashLength = 32;
+static const uint8_t kSthRootHashLength = 32;
 
 // Signed Tree Head as defined in section 3.5. of RFC6962
 struct NET_EXPORT SignedTreeHead {
@@ -28,7 +28,7 @@ struct NET_EXPORT SignedTreeHead {
 
   Version version;
   base::Time timestamp;
-  uint64 tree_size;
+  uint64_t tree_size;
   char sha256_root_hash[kSthRootHashLength];
   DigitallySigned signature;
 };