Use a pinned version of web-platform-tests/manifest.

third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py

Index: third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py
diff --git a/third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py b/third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py
index 954a026b1a72111431de106c8de43f1fd7860165..0ab512cb2a5626ca051ee2e755eef205037e7d4c 100644
--- a/third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py
+++ b/third_party/WebKit/Tools/Scripts/webkitpy/thirdparty/wpt/wpt/tools/wptserve/wptserve/server.py
@@ -252,9 +252,9 @@ class WebTestRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
             else:
                 try:
                     handler(request, response)
-                except HTTPException as error:
+                except HTTPException as e:
                     response.set_error(e.code, e.message)
-                except Exception as error:
+                except Exception as e:
                     if e.message:
                         err = [e.message]
                     else:
@@ -281,12 +281,12 @@ class WebTestRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
                 # Ensure that the whole request has been read from the socket
                 request.raw_input.read()
 
-        except socket.timeout as error:
+        except socket.timeout as e:
             self.log_error("Request timed out: %r", e)
             self.close_connection = True
             return
 
-        except Exception as error:
+        except Exception as e:
             err = traceback.format_exc()
             if response:
                 response.set_error(500, err)