webapps: Add cleanup task when opening up WebappActivity to clean old web apps

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
index b0b1bc88cbfdc6095a127fb0553a745cf4f81e3f..0d8bbb4c5235888de7dc95491b2e4920bc1dd234 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDataStorage.java
@@ -137,7 +137,8 @@ public class WebappDataStorage {
         mPreferences.edit().putLong(KEY_LAST_USED, System.currentTimeMillis()).commit();
     }
 
-    private long getLastUsedTime() {
+    /** Package private for use by WebappRegistry */

[gone, 2015/09/24 10:27:11]

nit: could've sworn I'd put a comment last time about not bothering to mention
why it's package private.  can you delete the one above, as well?

[Lalit Maganti, 2015/09/24 12:35:44]

Think you said something related but not for package private AFAIK. Removed
both.

+    long getLastUsedTime() {
         assert !ThreadUtils.runningOnUiThread();
         return mPreferences.getLong(KEY_LAST_USED, INVALID_LAST_USED);
     }