[Payments] Field trial and flag to abort payment request if no card.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index bfa6859e3b281212f3082582aa6129e56a255e71..aaf7aed5fb0ae4f26be2aba8d18fadd9505b98a9 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2072,6 +2072,12 @@ const FeatureEntry kFeatureEntries[] = {
      IDS_FLAGS_ENABLE_DEFAULT_MEDIA_SESSION_DESCRIPTION, kOsDesktop,
      MULTI_VALUE_TYPE(kEnableDefaultMediaSessionChoices)},
 #endif  // !defined(OS_ANDROID)
+#if defined(OS_ANDROID)
+    {"enable-no-card-abort", IDS_FLAGS_NO_CARD_ABORT,

[please use gerrit instead, 2016/10/20 20:27:44]

The "enable-no-card-abort" is used to generate a quick access URL for the
feature:

chrome://flags#enable-no-card-abort

The feature can be disabled, but the URL will remain the same, with "enable"
keyword in there. That's inconsistent. Let's remove the "enable" keyword from
the URL.

chrome://flags#no-card-abort

[sebsg, 2016/10/21 02:20:32]

Done.

+    IDS_FLAGS_NO_CARD_ABORT_DESCRIPTION, kOsAndroid,
+    ENABLE_DISABLE_VALUE_TYPE(switches::kEnablePaymentRequestNoCardAbort,

[please use gerrit instead, 2016/10/20 20:27:44]

You can use FEATURE_VALUE_TYPE() with ChromeFeatureList.

[sebsg, 2016/10/21 02:20:32]

Done.

+                              switches::kDisablePaymentRequestNoCardAbort)},
+#endif  // OS_ANDROID
     // NOTE: Adding new command-line switches requires adding corresponding
     // entries to enum "LoginCustomFlags" in histograms.xml. See note in
     // histograms.xml and don't forget to run AboutFlagsHistogramTest unit test.