[Web Payments] Add the shipping method section to the payment sheet

components/payments/content/payment_request.cc

Index: components/payments/content/payment_request.cc
diff --git a/components/payments/content/payment_request.cc b/components/payments/content/payment_request.cc
index 27397853dea788f35455313dd81bf316519e41f9..a19cc4f66aa3ba1cd0231732b10adfa08706b202 100644
--- a/components/payments/content/payment_request.cc
+++ b/components/payments/content/payment_request.cc
@@ -5,6 +5,7 @@
 #include "components/payments/content/payment_request.h"
 
 #include <algorithm>
+#include <set>
 #include <unordered_map>
 #include <utility>
 
@@ -68,6 +69,7 @@ void PaymentRequest::Init(
   PopulateValidatedMethodData(method_data);
   PopulateProfileCache();
   SetDefaultProfileSelections();
+  UpdateSelectedShippingOptionFromDetails();
 }
 
 void PaymentRequest::Show() {
@@ -387,4 +389,19 @@ bool PaymentRequest::ArePaymentOptionsSatisfied() {
   return true;
 }
 
+void PaymentRequest::UpdateSelectedShippingOptionFromDetails() {
+  selected_shipping_option_ = nullptr;
+
+  // As per the spec, the selected shipping option should initially be the last
+  // one in the array that has its selected field set to true.
+  auto selected_shipping_option_it = std::find_if(
+      details()->shipping_options.rbegin(), details()->shipping_options.rend(),
+      [](const payments::mojom::PaymentShippingOptionPtr& element) {
+        return element->selected;
+      });
+  if (selected_shipping_option_it != details()->shipping_options.rend()) {
+    selected_shipping_option_ = selected_shipping_option_it->get();

[Mathieu, 2017/03/09 19:07:03]

I think it's fine to keep the pointer because |details_| is owned by this
PaymentRequest and will outlive it. Maybe you can write that comment in the .h 

[anthonyvd, 2017/03/09 19:43:55]

Done.

+  }
+}
+
 }  // namespace payments