Add experiment to exercise AffiliationService with dummy data, plus add related UMA histograms.

components/password_manager/core/browser/affiliation_utils.cc

 // Copyright 2014 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.
 
 #include "components/password_manager/core/browser/affiliation_utils.h"
 
 #include <algorithm>
 #include <ostream>
 
 #include "base/base64.h"
@@ skipping 302 matching lines @@
   const std::string update_enabled = variations::GetVariationParamValue(
       kFieldTrialName, "propagate_password_changes_to_web");
 
   if (command_line.HasSwitch(switches::kDisableAffiliationBasedMatching))
     return false;
   if (command_line.HasSwitch(switches::kEnableAffiliationBasedMatching))
     return true;
   return LowerCaseEqualsASCII(update_enabled, "enabled");
 }
 
+bool IsAffiliationRequestsForDummyFacetsEnabled(
+    const base::CommandLine& command_line) {
+  const std::string synthesizing_enabled = variations::GetVariationParamValue(
+      kFieldTrialName, "affiliation_requests_for_dummy_facets");

[Ilya Sherman, 2015/04/21 00:38:05]

Out of curiousity, what is the advantage of using a param over a direct field
trial to control a simple enabled/disabled state?

[engedy, 2015/04/21 18:29:07]

We will never get to initializing this sub-feature unless the main feature is
enabled. So if they are controlled by two separate field trials, then the
sub-feature is only enabled for the intersection of users. That seemed not so
nice in terms of easy of analyzing the results.

Also, it seemed clearer to just have one field trial, with multiple experiment
groups, with each one having some set of sub-features enabled. WDYT?

[Ilya Sherman, 2015/04/21 20:11:27]

Got it.  Yeah, that sounds reasonable.  Thanks for the explanation =)

+  if (command_line.HasSwitch(switches::kDisableAffiliationBasedMatching))
+    return false;
+  if (command_line.HasSwitch(switches::kEnableAffiliationBasedMatching))
+    return true;
+  return LowerCaseEqualsASCII(synthesizing_enabled, "enabled");
+}
+
 bool IsValidAndroidFacetURI(const std::string& url) {
   FacetURI facet = FacetURI::FromPotentiallyInvalidSpec(url);
   return facet.IsValidAndroidFacetURI();
 }
 
 }  // namespace password_manager