[Payments] Add an entry for Payment Request to chrome://flags on iOS

ios/chrome/browser/experimental_flags.mm

Index: ios/chrome/browser/experimental_flags.mm
diff --git a/ios/chrome/browser/experimental_flags.mm b/ios/chrome/browser/experimental_flags.mm
index 3e55afffe705303bde742af6e5a6d4b7625518ff..9aa1ea7bbf248a3db315d3b0e149a32693847de9 100644
--- a/ios/chrome/browser/experimental_flags.mm
+++ b/ios/chrome/browser/experimental_flags.mm
@@ -19,6 +19,7 @@
 #include "base/strings/sys_string_conversions.h"
 #include "components/autofill/core/common/autofill_switches.h"
 #include "components/password_manager/core/common/password_manager_features.h"
+#include "components/payments/core/features.h"
 #include "components/signin/core/common/signin_switches.h"
 #include "components/variations/variations_associated_data.h"
 #include "ios/chrome/browser/chrome_switches.h"
@@ -173,22 +174,7 @@ bool IsPasswordGenerationEnabled() {
 }
 
 bool IsPaymentRequestEnabled() {

[noyau (Ping after 24h), 2017/07/06 15:33:28]

Can you get rid of this function and use IsEnabled directly? I'd like to get rid
of this whole file ultimately.

[Mathieu, 2017/07/06 15:34:30]

Done!

-  // This call activates the field trial, if needed, so it must come before any
-  // early returns.
-  std::string group_name =
-      base::FieldTrialList::FindFullName("IOSPaymentRequest");
-
-  // Check if the experimental flag is forced on or off.
-  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-  if (command_line->HasSwitch(switches::kEnablePaymentRequest)) {
-    return true;
-  } else if (command_line->HasSwitch(switches::kDisablePaymentRequest)) {
-    return false;
-  }
-
-  // Check if the Finch experiment is turned on.
-  return base::StartsWith(group_name, "Enabled",
-                          base::CompareCase::INSENSITIVE_ASCII);
+  return base::FeatureList::IsEnabled(payments::features::kWebPayments);
 }
 
 bool IsPhysicalWebEnabled() {