[Autofill] Sort profiles and credit cards by frecency in PaymentRequest.

chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java

Index: chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java b/chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java
index 060efdd3d95e4b480a5b0e869d0c23847e9cf440..c48b9da434e23650895d124356528947b27bc549 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/autofill/AutofillTestHelper.java
@@ -83,6 +83,15 @@ public class AutofillTestHelper {
         });
     }
 
+    List<CreditCard> getCreditCards() throws ExecutionException {
+        return ThreadUtils.runOnUiThreadBlocking(new Callable<List<CreditCard>>() {
+            @Override
+            public List<CreditCard> call() {
+                return PersonalDataManager.getInstance().getCreditCards();
+            }
+        });
+    }
+
     int getNumberOfCreditCards() throws ExecutionException {
         return ThreadUtils.runOnUiThreadBlocking(new Callable<Integer>() {
             @Override
@@ -114,6 +123,29 @@ public class AutofillTestHelper {
         waitForDataChanged();
     }
 
+    void setProfileUseStatsForTesting(final String guid, final int count, final int date)

[please use gerrit instead, 2016/05/24 20:21:48]

Please document the format for |date| and what will happen if I pass in negative
|count| or |date|. For example, say "count and date should be non-negative" and
then add "assert count >= 0 && date >= 0;" line in PersonalDataManager. This
will trigger only in debug builds.

[sebsg, 2016/05/24 21:41:22]

Done.

+            throws InterruptedException {
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                PersonalDataManager.getInstance().setProfileUseStatsForTesting(guid, count, date);
+            }
+        });
+        waitForDataChanged();
+    }
+
+    void setCreditCardUseStatsForTesting(final String guid, final int count, final int date)

[please use gerrit instead, 2016/05/24 20:21:48]

Ditto.

[sebsg, 2016/05/24 21:41:22]

Done.

+            throws InterruptedException {
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                PersonalDataManager.getInstance().setCreditCardUseStatsForTesting(
+                        guid, count, date);
+            }
+        });
+        waitForDataChanged();
+    }
+
     private void registerDataObserver() {
         ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override