Store URLs in WebappDataStorage, and purge them when history is cleared.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.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.Intent;
 import android.graphics.Bitmap;
 import android.graphics.Color;
 import android.graphics.drawable.Drawable;
@@ skipping 201 matching lines @@
         mWebappUma.commitMetrics();
     }
 
     @Override
     protected int getControlContainerLayoutId() {
         return R.layout.webapp_control_container;
     }
 
     @Override
     public void postInflationStartup() {
-        initializeSplashScreen();
+        initializeWebappData();
 
         super.postInflationStartup();
         WebappControlContainer controlContainer =
                 (WebappControlContainer) findViewById(R.id.control_container);
         mUrlBar = (WebappUrlBar) controlContainer.findViewById(R.id.webapp_url_bar);
     }
 
     /**
      * @return Structure containing data about the webapp currently displayed.
      */
     WebappInfo getWebappInfo() {
         return mWebappInfo;
     }
 
-    private void initializeSplashScreen() {
+    private void initializeWebappData() {
         final int backgroundColor = ColorUtils.getOpaqueColor(mWebappInfo.backgroundColor(
                 ApiCompatibilityUtils.getColor(getResources(), R.color.webapp_default_bg)));
 
         mSplashScreen = new FrameLayout(this);
         mSplashScreen.setBackgroundColor(backgroundColor);
 
         ViewGroup contentView = (ViewGroup) findViewById(android.R.id.content);
         contentView.addView(mSplashScreen);
 
         mWebappUma.splashscreenVisible();
         mWebappUma.recordSplashscreenBackgroundColor(mWebappInfo.hasValidBackgroundColor()
                 ? WebappUma.SPLASHSCREEN_COLOR_STATUS_CUSTOM
                 : WebappUma.SPLASHSCREEN_COLOR_STATUS_DEFAULT);
         mWebappUma.recordSplashscreenThemeColor(mWebappInfo.hasValidThemeColor()
                 ? WebappUma.SPLASHSCREEN_COLOR_STATUS_CUSTOM
                 : WebappUma.SPLASHSCREEN_COLOR_STATUS_DEFAULT);
 
+        // The scope may have been purged by the user clearing their history. It is
+        // needed to be able to launch a webapp from a notification. Make sure that the
+        // scope exists by restoring it on webapp launch; this method will no-op if the
+        // scope does exist as it should not be possible to overwrite any set scope.
+        WebappDataStorage.setScope(this, mWebappInfo.id(), mWebappInfo.uri().toString());
+
+        // Retrieve the splash image if it exists.
         WebappDataStorage.open(this, mWebappInfo.id()).getSplashScreenImage(
                 new WebappDataStorage.FetchCallback<Bitmap>() {
                     @Override
                     public void onDataRetrieved(Bitmap splashImage) {
                         initializeSplashScreenWidgets(backgroundColor, splashImage);
                     }
                 });
     }
 
     private void initializeSplashScreenWidgets(int backgroundColor, Bitmap splashImage) {
@@ skipping 304 matching lines @@
         return visible;
     }
 
     // We're temporarily disable CS on webapp since there are some issues. (http://crbug.com/471950)
     // TODO(changwan): re-enable it once the issues are resolved.
     @Override
     protected boolean isContextualSearchAllowed() {
         return false;
     }
 }