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

net/data/proxy_resolver_v8_tracing_unittest/dns_depending_on_url.js

Index: net/data/proxy_resolver_v8_tracing_unittest/dns_depending_on_url.js
diff --git a/net/data/proxy_resolver_v8_tracing_unittest/dns_depending_on_url.js b/net/data/proxy_resolver_v8_tracing_unittest/dns_depending_on_url.js
new file mode 100644
index 0000000000000000000000000000000000000000..ac6611077db2c19ab9bc9b150087e0121535a0eb
--- /dev/null
+++ b/net/data/proxy_resolver_v8_tracing_unittest/dns_depending_on_url.js
@@ -0,0 +1,17 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This proxy script has different DNS dependencies based on whether the URL
+// contains "UseMyIpAddress". The final proxy list however is the same.
+function FindProxyForURL(url, host) {
+  if (url.indexOf("UseMyIpAddress") == -1) {
+    if (!myIpAddress())
+      return null;
+  } else {
+    if (!dnsResolve(host))
+      return null;
+  }
+
+  return "PROXY foopy:47";
+}