[Payments] Add CanMakePayment metrics.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 09d1568867fddb96c9060b75e995b25950d366a2..390399c6d642730d9e04a86b43141bfca8e83bde 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -45070,6 +45070,52 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram
+    name="PaymentRequest.CanMakePayment.NotUsed.WithShowEffectOnCompletion"
+    enum="PaymentRequestFlowCompletionStatus">
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    Whether the flow was completed when CanMakePayment was not called by the
+    merchant.
+  </summary>
+</histogram>
+
+<histogram name="PaymentRequest.CanMakePayment.Usage" enum="Boolean">
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    Whether the merchant used the CanMakePayment method during a Payment
+    Request.
+  </summary>
+</histogram>
+
+<histogram name="PaymentRequest.CanMakePayment.Used.EffectOnShow"
+    enum="PaymentRequestCanMakePaymentEffectOnShow">
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    The effect of the CanMakePayment return value on whether Show was called.
+  </summary>
+</histogram>
+
+<histogram
+    name="PaymentRequest.CanMakePayment.Used.FalseWithShowEffectOnCompletion"
+    enum="PaymentRequestFlowCompletionStatus">
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    Whether the flow was completed when CanMakePayment was called by the
+    merchant and returned false.
+  </summary>
+</histogram>
+
+<histogram
+    name="PaymentRequest.CanMakePayment.Used.TrueWithShowEffectOnCompletion"
+    enum="PaymentRequestFlowCompletionStatus">
+  <owner>sebsg@chromium.org</owner>
+  <summary>
+    Whether the flow was completed when CanMakePayment was called by the
+    merchant and returned true.
+  </summary>
+</histogram>
+
 <histogram name="PaymentRequest.CheckoutFunnel.Aborted"
     enum="PaymentRequestAbortReason">
   <owner>sebsg@chromium.org</owner>
@@ -100193,6 +100239,18 @@ value.
   <int value="8" label="Other"/>
 </enum>
 
+<enum name="PaymentRequestCanMakePaymentEffectOnShow" type="int">
+  <int value="0" label="False and not shown"/>

[please use gerrit instead, 2017/01/23 21:04:33]

Nit: would it be too much to write "canMakePayment() returned false and show()
was not called"?

[sebsg, 2017/01/23 22:57:23]

Done.

+  <int value="1" label="False and shown"/>
+  <int value="2" label="True and not shown"/>
+  <int value="3" label="True and shown"/>
+</enum>
+
+<enum name="PaymentRequestFlowCompletionStatus" type="int">
+  <int value="0" label="Completed"/>
+  <int value="1" label="Aborted"/>
+</enum>
+
 <enum name="PaymentRequestPaymentMethods" type="int">
   <int value="0" label="Autofill credit cards"/>
   <int value="1" label="Android Pay"/>