[Payments] Show complete profiles first and limit to 4 suggestions.

chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java

Index: chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
index 360ab4ad67ee38eef702f31cb2ffa1f82a82e97e..47fa6873468e0e40b6283ef5f99bbd29f7e21e39 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/payments/PaymentRequestImpl.java
@@ -45,6 +45,8 @@ import org.json.JSONObject;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -75,6 +77,8 @@ public class PaymentRequestImpl implements PaymentRequest, PaymentRequestUI.Clie
 
     private static final String TAG = "cr_PaymentRequest";
 
+    private static final int SUGGESTIONS_LIMIT = 4;
+
     private static PaymentRequestServiceObserverForTest sObserverForTest;
 
     private final Handler mHandler = new Handler();
@@ -225,7 +229,6 @@ public class PaymentRequestImpl implements PaymentRequest, PaymentRequestUI.Clie
         if (requestShipping) {
             mAddressEditor = new AddressEditor();
             List<AutofillAddress> addresses = new ArrayList<>();
-            int firstCompleteAddressIndex = SectionInformation.NO_SELECTION;
 
             for (int i = 0; i < profiles.size(); i++) {
                 AutofillProfile profile = profiles.get(i);
@@ -233,23 +236,41 @@ public class PaymentRequestImpl implements PaymentRequest, PaymentRequestUI.Clie
 
                 boolean isComplete = mAddressEditor.isProfileComplete(profile);
                 addresses.add(new AutofillAddress(profile, isComplete));
-                if (isComplete && firstCompleteAddressIndex == SectionInformation.NO_SELECTION
-                        && !mMerchantNeedsShippingAddress) {
-                    firstCompleteAddressIndex = i;
-                }
             }
 
-            // The shipping address section automatically selects the first complete entry.
+            // Suggest complete addresses first.
+            Collections.sort(addresses, new Comparator<AutofillAddress>() {
+                @Override
+                public int compare(AutofillAddress a, AutofillAddress b) {
+                    if (a.isComplete() == b.isComplete()) {

[please use gerrit instead, 2016/07/07 13:59:36]

Make AutofillAddress and AutofillContact implement a new interface, let's call
it Completable.

public interface Completable {
  boolean isComplete();
}

Then you have a common comparator for addresses and contacts.

[sebsg, 2016/07/08 07:54:52]

Done.

+                        return 0;
+                    } else if (a.isComplete()) {
+                        return -1;
+                    } else {
+                        return 1;
+                    }
+                }
+            });
+
+            // Limit the number of suggestions.
+            List<AutofillAddress> topAddresses = new ArrayList<AutofillAddress>(

[please use gerrit instead, 2016/07/07 13:59:36]

addresses = addresses.subList(0, Math.min(addresses.size(), SUGGESTIONS_LIMIT));

[sebsg, 2016/07/08 07:54:51]

Done.

+                    addresses.subList(0, Math.min(addresses.size(), SUGGESTIONS_LIMIT)));
+
+            // Automatically select the first complete address if one is present and if the merchant
+            // does not require a shipping address to calculate shipping costs.
+            int firstCompleteAddressIndex =
+                    (!mMerchantNeedsShippingAddress && topAddresses.size() > 0

[please use gerrit instead, 2016/07/07 13:59:36]

I think "!addresses.isEmpty()" is more canonical than "addresses.size() > 0".

[sebsg, 2016/07/08 07:54:52]

Done.

+                            && topAddresses.get(0).isComplete())
+                                    ? 0 : SectionInformation.NO_SELECTION;
             mShippingAddressesSection =
                     new SectionInformation(PaymentRequestUI.TYPE_SHIPPING_ADDRESSES,
-                            firstCompleteAddressIndex, addresses);
+                            firstCompleteAddressIndex, topAddresses);
         }
 
         if (requestPayerPhone || requestPayerEmail) {
             Set<String> uniqueContactInfos = new HashSet<>();
             mContactEditor = new ContactEditor(requestPayerPhone, requestPayerEmail);
             List<AutofillContact> contacts = new ArrayList<>();
-            int firstCompleteContactIndex = SectionInformation.NO_SELECTION;
 
             for (int i = 0; i < profiles.size(); i++) {
                 AutofillProfile profile = profiles.get(i);
@@ -270,17 +291,34 @@ public class PaymentRequestImpl implements PaymentRequest, PaymentRequestUI.Clie
                         boolean isComplete =
                                 mContactEditor.isContactInformationComplete(phone, email);
                         contacts.add(new AutofillContact(profile, phone, email, isComplete));
-                        if (isComplete
-                                && firstCompleteContactIndex == SectionInformation.NO_SELECTION) {
-                            firstCompleteContactIndex = i;
-                        }
                     }
                 }
             }
 
-            // The contact section automatically selects the first complete entry.
+            // Suggest complete contact infos first.
+            Collections.sort(contacts, new Comparator<AutofillContact>() {
+                @Override
+                public int compare(AutofillContact a, AutofillContact b) {
+                    if (a.isComplete() == b.isComplete()) {

[please use gerrit instead, 2016/07/07 13:59:36]

Would this be considered bad? ;-)

return (a.isComplete() ? 1 : 0) - (b.isComplete() ? 1 : 0);

[sebsg, 2016/07/08 07:54:52]

I prefer the current version but I'll defer decision to you :)

+                        return 0;
+                    } else if (a.isComplete()) {
+                        return -1;
+                    } else {
+                        return 1;
+                    }
+                }
+            });
+
+            // Limit the number of suggestions.
+            List<AutofillContact> topContacts = new ArrayList<AutofillContact>(

[please use gerrit instead, 2016/07/07 13:59:36]

contacts = contacts.subList(...);

[sebsg, 2016/07/08 07:54:52]

Done.

+                    contacts.subList(0, Math.min(contacts.size(), SUGGESTIONS_LIMIT)));
+
+            // Automatically select the first complete address if one is present.
+            int firstCompleteContactIndex = (topContacts.size() > 0

[please use gerrit instead, 2016/07/07 13:59:36]

!contacts.isEmpty()

[sebsg, 2016/07/08 07:54:51]

Done.

+                        && topContacts.get(0).isComplete())
+                                ? 0 : SectionInformation.NO_SELECTION;
             mContactSection = new SectionInformation(
-                    PaymentRequestUI.TYPE_CONTACT_DETAILS, firstCompleteContactIndex, contacts);
+                    PaymentRequestUI.TYPE_CONTACT_DETAILS, firstCompleteContactIndex, topContacts);
         }
 
         mPendingApps = new ArrayList<>(mApps);