[Reland] Refactor WebappRegistry into a singleton instance.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
index 7022ef318d8d07909215a9e15830a78a08f042f5..ac8358bab00dece4e6e3f4a641342c826f2ccbd5 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java
@@ -60,8 +60,6 @@ public class WebappActivity extends FullScreenActivity {
 
     protected WebappInfo mWebappInfo;
 
-    private boolean mOldWebappCleanupStarted;
-
     private ViewGroup mSplashScreen;
     private WebappUrlBar mUrlBar;
 
@@ -126,7 +124,14 @@ public class WebappActivity extends FullScreenActivity {
     @Override
     public void preInflationStartup() {
         WebappInfo info = WebappInfo.create(getIntent());
-        if (info != null) mWebappInfo = info;
+
+        String id = "";
+        if (info != null) {
+            mWebappInfo = info;
+            id = info.id();
+        }
+
+        WebappRegistry.warmUpSharedPrefs(id);

[Peter Wen, 2016/09/29 18:24:47]

To get the full benefit of warming up shared prefs on N you'll have to do
something similar to ChromeBrowserInitializer#warmUpSharedPrefs and start an
AsyncTask on N. Since it may end up being a lot of preferences to warm up (every
PWA), I think it's worth it, probably not necessary to add to
NotificationService, but your choice.

[dominickn, 2016/09/30 00:17:01]

This will only warm two preferences: the WebappRegistry, and the specific
preference file for the PWA being opened right now (= id). The rest of the PWAs
will have their preferences warmed in DeferredStartupHandler. Will an async task
complete before postInflationStartup?

[Peter Wen, 2016/09/30 13:59:19]

Ah, right. Good point, didn't realize about the id, so that's not as bad.
Probably not worth the overhead of another AsyncTask as you need it so soon
after.

You'll need to then add a StrictMode policy whitelist for this call as on N
these warm up calls read disk and cause violations.

[dominickn, 2016/10/04 01:09:17]

Done. Thanks for the explanations on this. :)

 
         ScreenOrientationProvider.lockOrientation((byte) mWebappInfo.orientation(), this);
         super.preInflationStartup();
@@ -195,13 +200,6 @@ public class WebappActivity extends FullScreenActivity {
             updateTaskDescription();
         }
         super.onResume();
-
-        // Kick off the old web app cleanup (if we haven't already) now that we have queued the
-        // current web app's storage to be opened.
-        if (!mOldWebappCleanupStarted) {
-            WebappRegistry.unregisterOldWebapps(System.currentTimeMillis());
-            mOldWebappCleanupStarted = true;
-        }
     }
 
     @Override
@@ -262,25 +260,20 @@ public class WebappActivity extends FullScreenActivity {
     }
 
     protected void initializeSplashScreenWidgets(final int backgroundColor) {
-        WebappRegistry.getWebappDataStorage(
-                mWebappInfo.id(), new WebappRegistry.FetchWebappDataStorageCallback() {
-                    @Override
-                    public void onWebappDataStorageRetrieved(WebappDataStorage storage) {
-                        if (storage == null) {
-                            onStorageIsNull(backgroundColor);
-                            return;
-                        }
-                        updateStorage(storage);
-
-                        // Retrieve the splash image if it exists.
-                        storage.getSplashScreenImage(new WebappDataStorage.FetchCallback<Bitmap>() {
-                            @Override
-                            public void onDataRetrieved(Bitmap splashImage) {
-                                initializeSplashScreenWidgets(backgroundColor, splashImage);
-                            }
-                        });
-                    }
-                });
+        WebappDataStorage storage =
+                WebappRegistry.getInstance().getWebappDataStorage(mWebappInfo.id());
+        if (storage == null) {
+            onStorageIsNull(backgroundColor);
+            return;
+        }
+
+        updateStorage(storage);
+        storage.getSplashScreenImage(new WebappDataStorage.FetchCallback<Bitmap>() {
+            @Override
+            public void onDataRetrieved(Bitmap splashImage) {
+                initializeSplashScreenWidgets(backgroundColor, splashImage);
+            }
+        });
     }
 
     protected void onStorageIsNull(int backgroundColor) {}