Add a histogram (Net.PacResultForStrippedUrl) that estimates how often PAC scripts depend on the UR…

net/data/proxy_resolver_v8_tracing_unittest/alert_url.js

Index: net/data/proxy_resolver_v8_tracing_unittest/alert_url.js
diff --git a/chrome/test/data/extensions/api_test/executescript/http204/at_document_end.js b/net/data/proxy_resolver_v8_tracing_unittest/alert_url.js
similarity index 66%
copy from chrome/test/data/extensions/api_test/executescript/http204/at_document_end.js
copy to net/data/proxy_resolver_v8_tracing_unittest/alert_url.js
index 5b0e04991e627c97943dd6628ec098aaf692abec..3cc14c946f15b946c6e46f34478c7ad82b31702f 100644
--- a/chrome/test/data/extensions/api_test/executescript/http204/at_document_end.js
+++ b/net/data/proxy_resolver_v8_tracing_unittest/alert_url.js
@@ -2,4 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-window.documentEnd = window.documentEnd ? documentEnd + 1 : 1;
+function FindProxyForURL(url, host) {
+  alert(url);
+  return "PROXY foobar:99";
+}