Make the gdb Vector pretty-printer work with Python version >= 3.

third_party/WebKit/Tools/gdb/webkit.py

Index: third_party/WebKit/Tools/gdb/webkit.py
diff --git a/third_party/WebKit/Tools/gdb/webkit.py b/third_party/WebKit/Tools/gdb/webkit.py
index 3aa50535a6bee27c5306513eab310bde19d99d33..53a2a875ea8fbddd610d47c7f1274441e784a76c 100644
--- a/third_party/WebKit/Tools/gdb/webkit.py
+++ b/third_party/WebKit/Tools/gdb/webkit.py
@@ -325,7 +325,7 @@ class WTFVectorPrinter:
         def __iter__(self):
             return self
 
-        def next(self):
+        def __next__(self):
             if self.item == self.finish:
                 raise StopIteration
             count = self.count
@@ -334,6 +334,10 @@ class WTFVectorPrinter:
             self.item += 1
             return ('[%d]' % count, element)
 
+        # Python version < 3 compatibility:
+        def next(self):
+            return self.__next__()
+
     def __init__(self, val):
         self.val = val