KeyPrefix#createKey(int) to generate dynamic SharedPrefs key with ints.

This will be used in at least two places: OmniboxSuggestion and
CtrSuppression.

Bug: 1022108
Change-Id: I627aae9bd0bc3c9f260371b2a4ac0ecf5f3dc992
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2019940Reviewed-by: Natalie Chouinard <chouinard@chromium.org>
Commit-Queue: Henrique Nakashima <hnakashima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#735525}

chrome/browser/preferences/android/java/src/org/chromium/chrome/browser/preferences/KeyPrefix.java

@@ -19,11 +19,18 @@ public class KeyPrefix {
     }
 
     /**
-     * @param suffix A non-empty string. The '*' character is reserved.
+     * @param stem A non-empty string. The '*' character is reserved.
      * @return The complete SharedPreferences key to be passed to {@link SharedPreferencesManager}.
      */
-    public String createKey(String suffix) {
-        return mPrefix + suffix;
+    public String createKey(String stem) {
+        return mPrefix + stem;
+    }
+    /**
+     * @param index An int to generate a unique key.
+     * @return The complete SharedPreferences key to be passed to {@link SharedPreferencesManager}.
+     */
+    public String createKey(int index) {
+        return mPrefix + index;
     }
 
     String pattern() {

chrome/browser/preferences/android/java/src/org/chromium/chrome/browser/preferences/KeyPrefixTest.java

@@ -29,9 +29,11 @@ public class KeyPrefixTest {
 
         assertEquals(prefix.createKey("DynamicKey"), "Chrome.Feature.KP.DynamicKey");
         assertEquals(prefix.createKey("Level.DynamicKey"), "Chrome.Feature.KP.Level.DynamicKey");
+        assertEquals(prefix.createKey(42), "Chrome.Feature.KP.42");
 
         assertTrue(prefix.hasGenerated("Chrome.Feature.KP.DynamicKey"));
         assertTrue(prefix.hasGenerated("Chrome.Feature.KP.Level.DynamicKey"));
+        assertTrue(prefix.hasGenerated("Chrome.Feature.KP.42"));
         assertFalse(prefix.hasGenerated("OtherKey"));
     }