Remove the context argument from all WebappRegistry/WebappDataStorage methods.

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

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.webapps;
 
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.os.AsyncTask;
 
+import org.chromium.base.ContextUtils;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.browsing_data.UrlFilter;
 import org.chromium.chrome.browser.browsing_data.UrlFilterBridge;
 
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
@@ skipping 28 matching lines @@
 
     /**
      * Called when a retrieval of the stored WebappDataStorage occurs. The storage parameter will
      * be null if the web app queried for was not in the registry.
      */
     public interface FetchWebappDataStorageCallback {
         void onWebappDataStorageRetrieved(WebappDataStorage storage);
     }
 
     /**
-     * Registers the existence of a web app, creates the SharedPreference for it, and runs the
+     * Registers the existence of a web app, creates a SharedPreference entry for it, and runs the
      * supplied callback (if not null) on the UI thread with the resulting WebappDataStorage object.
-     * @param context  Context to open the registry with.
      * @param webappId The id of the web app to register.
      * @param callback The callback to run with the WebappDataStorage argument.
      * @return The storage object for the web app.
      */
-    public static void registerWebapp(final Context context, final String webappId,
+    public static void registerWebapp(final String webappId,
             final FetchWebappDataStorageCallback callback) {
         new AsyncTask<Void, Void, WebappDataStorage>() {
             @Override
             protected final WebappDataStorage doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);

[Peter Wen, 2016/09/21 14:58:41]

Same as above, openSharedPreferences doesn't need a context.

[dominickn, 2016/09/22 03:47:00]

Done.

                 // The set returned by getRegisteredWebappIds must be treated as immutable, so we
                 // make a copy to edit and save.
                 Set<String> webapps = new HashSet<>(getRegisteredWebappIds(preferences));
                 boolean added = webapps.add(webappId);
                 assert added;
 
                 preferences.edit().putStringSet(KEY_WEBAPP_SET, webapps).apply();
 
                 // Create the WebappDataStorage and update the last used time, so we can guarantee
                 // that a web app which appears in the registry will have a
                 // last used time != WebappDataStorage.LAST_USED_INVALID.
                 WebappDataStorage storage = new WebappDataStorage(context, webappId);

[Peter Wen, 2016/09/21 14:58:41]

Since WebappDataStorage doesn't need context, no need for this local context
variable. Also, preference should be given to doing:

Context appContext = ContextUtils.getApplicationContext();

As it helps make the distinction clearer.

[dominickn, 2016/09/22 03:47:00]

Done.

                 storage.updateLastUsedTime();
                 return storage;
             }
 
             @Override
             protected final void onPostExecute(WebappDataStorage storage) {
                 if (callback != null) callback.onWebappDataStorageRetrieved(storage);
             }
         }.execute();
     }
 
     /**
      * Runs the callback, supplying the WebappDataStorage object for webappId, or null if the web
      * app has not been registered.
-     * @param context  Context to open the registry with.
      * @param webappId The id of the web app to register.
      * @return The storage object for the web app, or null if webappId is not registered.
      */
-    public static void getWebappDataStorage(final Context context, final String webappId,
+    public static void getWebappDataStorage(final String webappId,
             final FetchWebappDataStorageCallback callback) {
         new AsyncTask<Void, Void, WebappDataStorage>() {
             @Override
             protected final WebappDataStorage doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);
                 if (getRegisteredWebappIds(preferences).contains(webappId)) {
                     WebappDataStorage storage = WebappDataStorage.open(context, webappId);
                     return storage;
                 }
                 return null;
             }
 
             @Override
             protected final void onPostExecute(WebappDataStorage storage) {
                 assert callback != null;
                 callback.onWebappDataStorageRetrieved(storage);
             }
         }.execute();
     }
 
     /**
      * Runs the callback, supplying the WebappDataStorage object whose scope most closely matches
      * the provided URL, or null if a matching web app cannot be found. The most closely matching
      * scope is the longest scope which has the same prefix as the URL to open.
-     * @param context  Context to open the registry with.
      * @param url      The URL to search for.
      * @return The storage object for the web app, or null if webappId is not registered.
      */
-    public static void getWebappDataStorageForUrl(final Context context, final String url,
+    public static void getWebappDataStorageForUrl(final String url,
             final FetchWebappDataStorageCallback callback) {
         new AsyncTask<Void, Void, WebappDataStorage>() {
             @Override
             protected final WebappDataStorage doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);
                 WebappDataStorage bestMatch = null;
                 int largestOverlap = 0;
                 for (String id : getRegisteredWebappIds(preferences)) {
                     WebappDataStorage storage = WebappDataStorage.open(context, id);
                     String scope = storage.getScope();
                     if (url.startsWith(scope) && scope.length() > largestOverlap) {
                         bestMatch = storage;
                         largestOverlap = scope.length();
                     }
                 }
                 return bestMatch;
             }
 
             protected final void onPostExecute(WebappDataStorage storage) {
                 assert callback != null;
                 callback.onWebappDataStorageRetrieved(storage);
             }
         }.execute();
     }
 
     /**
      * Asynchronously retrieves the list of web app IDs which this registry is aware of.
-     * @param context  Context to open the registry with.
      * @param callback Called when the set has been retrieved. The set may be empty.
      */
     @VisibleForTesting
-    public static void getRegisteredWebappIds(final Context context, final FetchCallback callback) {
+    public static void getRegisteredWebappIds(final FetchCallback callback) {
         new AsyncTask<Void, Void, Set<String>>() {
             @Override
             protected final Set<String> doInBackground(Void... nothing) {
-                return getRegisteredWebappIds(openSharedPreferences(context));
+                return getRegisteredWebappIds(
+                        openSharedPreferences(ContextUtils.getApplicationContext()));
             }
 
             @Override
             protected final void onPostExecute(Set<String> result) {
                 assert callback != null;
                 callback.onWebappIdsRetrieved(result);
             }
         }.execute();
     }
 
     /**
      * 1. Deletes the data for all "old" web apps.
      * "Old" web apps have not been opened by the user in the last 3 months, or have had their last
      * used time set to 0 by the user clearing their history. Cleanup is run, at most, once a month.
      * 2. Deletes the data for all WebAPKs that have been uninstalled in the last month.
      *
-     * @param context     Context to open the registry with.
      * @param currentTime The current time which will be checked to decide if the task should be run
      *                    and if a web app should be cleaned up.
      */
-    static void unregisterOldWebapps(final Context context, final long currentTime) {
+    static void unregisterOldWebapps(final long currentTime) {
         new AsyncTask<Void, Void, Void>() {
             @Override
             protected final Void doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);
                 long lastCleanup = preferences.getLong(KEY_LAST_CLEANUP, 0);
                 if ((currentTime - lastCleanup) < FULL_CLEANUP_DURATION) return null;
 
                 Set<String> currentWebapps = getRegisteredWebappIds(preferences);
                 Set<String> retainedWebapps = new HashSet<>(currentWebapps);
                 PackageManager pm = context.getPackageManager();
                 for (String id : currentWebapps) {
                     WebappDataStorage storage = new WebappDataStorage(context, id);
                     String webApkPackage = storage.getWebApkPackageName();
@@ skipping 27 matching lines @@
             return false;
         }
         return true;
     }
 
     /**
      * Deletes the data of all web apps whose url matches |urlFilter|, as well as the registry
      * tracking those web apps.
      */
     @VisibleForTesting
-    static void unregisterWebappsForUrls(
-            final Context context, final UrlFilter urlFilter, final Runnable callback) {
+    static void unregisterWebappsForUrls(final UrlFilter urlFilter, final Runnable callback) {
         new AsyncTask<Void, Void, Void>() {
             @Override
             protected final Void doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);
                 Set<String> registeredWebapps =
                         new HashSet<>(getRegisteredWebappIds(preferences));
                 Set<String> webappsToUnregister = new HashSet<>();
                 for (String id : registeredWebapps) {
                     if (urlFilter.matchesUrl(WebappDataStorage.open(context, id).getUrl())) {
                         WebappDataStorage.deleteDataForWebapp(context, id);
                         webappsToUnregister.add(id);
                     }
                 }
@@ skipping 14 matching lines @@
             @Override
             protected final void onPostExecute(Void nothing) {
                 assert callback != null;
                 callback.run();
             }
         }.execute();
     }
 
     @CalledByNative
     static void unregisterWebappsForUrls(
-            Context context, final UrlFilterBridge urlFilter, final long callbackPointer) {
-        unregisterWebappsForUrls(context, urlFilter, new Runnable() {
+            final UrlFilterBridge urlFilter, final long callbackPointer) {
+        unregisterWebappsForUrls(urlFilter, new Runnable() {
             @Override
             public void run() {
                 urlFilter.destroy();
                 nativeOnWebappsUnregistered(callbackPointer);
             }
         });
     }
 
     /**
      * Deletes the URL and scope, and sets the last used time to 0 for all web apps whose url
      * matches |urlFilter|.
      */
     @VisibleForTesting
-    static void clearWebappHistoryForUrls(
-            final Context context, final UrlFilter urlFilter, final Runnable callback) {
+    static void clearWebappHistoryForUrls(final UrlFilter urlFilter, final Runnable callback) {
         new AsyncTask<Void, Void, Void>() {
             @Override
             protected final Void doInBackground(Void... nothing) {
+                Context context = ContextUtils.getApplicationContext();
                 SharedPreferences preferences = openSharedPreferences(context);
                 for (String id : getRegisteredWebappIds(preferences)) {
                     if (urlFilter.matchesUrl(WebappDataStorage.open(context, id).getUrl())) {
                         WebappDataStorage.clearHistory(context, id);
                     }
                 }
                 return null;
             }
 
             @Override
             protected final void onPostExecute(Void nothing) {
                 assert callback != null;
                 callback.run();
             }
         }.execute();
     }
 
     @CalledByNative
     static void clearWebappHistoryForUrls(
-            Context context, final UrlFilterBridge urlFilter, final long callbackPointer) {
-        clearWebappHistoryForUrls(context, urlFilter, new Runnable() {
+            final UrlFilterBridge urlFilter, final long callbackPointer) {
+        clearWebappHistoryForUrls(urlFilter, new Runnable() {
             @Override
             public void run() {
                 urlFilter.destroy();
                 nativeOnClearedWebappHistory(callbackPointer);
             }
         });
     }
 
     private static SharedPreferences openSharedPreferences(Context context) {
         return context.getSharedPreferences(REGISTRY_FILE_NAME, Context.MODE_PRIVATE);
     }
 
     private static Set<String> getRegisteredWebappIds(SharedPreferences preferences) {
         // Wrap with unmodifiableSet to ensure it's never modified. See crbug.com/568369.
         return Collections.unmodifiableSet(
                 preferences.getStringSet(KEY_WEBAPP_SET, Collections.<String>emptySet()));
     }
 
     private WebappRegistry() {
     }
 
     private static native void nativeOnWebappsUnregistered(long callbackPointer);
     private static native void nativeOnClearedWebappHistory(long callbackPointer);
 }