Add flag to enable/disable affiliaton based matching.

components/password_manager/core/browser/affiliation_utils.cc

Index: components/password_manager/core/browser/affiliation_utils.cc
diff --git a/components/password_manager/core/browser/affiliation_utils.cc b/components/password_manager/core/browser/affiliation_utils.cc
index ad9e0ac6ec49574affe252e8b545d8e474bdf344..1d94edb28e50de738ccd3c4c17d3c9d93e7b84de 100644
--- a/components/password_manager/core/browser/affiliation_utils.cc
+++ b/components/password_manager/core/browser/affiliation_utils.cc
@@ -7,8 +7,11 @@
 #include <algorithm>
 
 #include "base/base64.h"
+#include "base/command_line.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_util.h"
+#include "components/password_manager/core/common/password_manager_switches.h"
+#include "components/variations/variations_associated_data.h"
 #include "net/base/escape.h"
 #include "url/third_party/mozilla/url_parse.h"
 #include "url/url_canon_stdstring.h"
@@ -280,4 +283,15 @@ bool AreEquivalenceClassesEqual(const AffiliatedFacets& a,
   return std::equal(a_sorted.begin(), a_sorted.end(), b_sorted.begin());
 }
 
+bool IsAffiliationBasedMatchingEnabled(const base::CommandLine& command_line) {
+  if (command_line.HasSwitch(switches::kDisableAffiliationBasedMatching))
+    return false;
+
+  if (command_line.HasSwitch(switches::kEnableAffiliationBasedMatching))
+    return true;
+
+  return variations::GetVariationParamValue("AffiliationBasedMatching",
+                                            "enabled") == "true";

[Garrett Casto, 2015/02/03 05:32:41]

Alexei can talk more about how appropriate it is to use this function instead of
base::FieldTrial::FindFullName(), but I think that if you want to use forcing
flags, this call needs to go above the return values from the command line flags
(go/finch-and-flags).

[Alexei Svitkine (slow), 2015/02/03 17:27:41]

Indeed, it's needed to activate the trial.

Using params like this provides more flexibility. However, can you confirm that
this is only used from the browser process? If it's used from subprocesses, then
variation params will not work.

[engedy, 2015/02/03 18:24:27]

Thanks. Then I might as well just use field trials, because this will be used
solely as staged roll-out mechanism and kill switch.

I will not be accessing the experiment from subprocesses.

+}
+
 }  // namespace password_manager