Enable (optional) blocking of webrequests in case a PAC script cannot be fetched or is invalid.

chrome/browser/automation/automation_provider.cc

Index: chrome/browser/automation/automation_provider.cc
diff --git a/chrome/browser/automation/automation_provider.cc b/chrome/browser/automation/automation_provider.cc
index 5a86ca7cbfeede15bea7f2cd7a488d55a7ed6ec2..a5a668631e56632fe4ef2ee7eb65b08c2fdc86b7 100644
--- a/chrome/browser/automation/automation_provider.cc
+++ b/chrome/browser/automation/automation_provider.cc
@@ -550,6 +550,10 @@ class SetProxyConfigTask : public Task {
     if (dict.GetString(automation::kJSONProxyPacUrl, &pac_url)) {
       pc->set_pac_url(GURL(pac_url));
     }
+    bool pac_mandatory;
+    if (dict.GetBoolean(automation::kJSONProxyPacMandatory, &pac_mandatory)) {
+      pc->set_pac_mandatory(pac_mandatory);
+    }
     std::string proxy_bypass_list;
     if (dict.GetString(automation::kJSONProxyBypassList, &proxy_bypass_list)) {
       pc->proxy_rules().bypass_rules.ParseFromString(proxy_bypass_list);