Open the notification URL (not the web app start_url) when deep-linking into standalone mode.

chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java

Index: chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java b/chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java
index 35d77ec8344a3cb2e44bb5406369659789cf84e0..31828cbacbe99d505739e7091cd9eb722d851a53 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ChromeServiceTabLauncher.java
@@ -83,6 +83,9 @@ public class ChromeServiceTabLauncher extends ServiceTabLauncher {
 
                         @Override
                         protected final void onPostExecute(Intent intent) {
+                            // Replace the web app URL with the URL from the notification. This is
+                            // within the webapp's scope, so it is valid.
+                            intent.putExtra(ShortcutHelper.EXTRA_URL, url);
                             intent.putExtra(ShortcutHelper.EXTRA_SOURCE,
                                     ShortcutSource.NOTIFICATION);
                             tabDelegate.createNewStandaloneFrame(intent);