🕸️ Add FLAG_ACTIVITY_NEW_DOCUMENT to WebappActivity Intents.

On Samsung Lollipop devices the Intents used to communicate with a
foreground WebappActivity were causing a new instance of the
WebappActivity to be launched instead of causing onNewIntent of the
current Activity to be run. This only occurs when a
ChromeTabbedActivity is in the background, when it is not, onNewIntent
is called properly.

I'm not sure what is special about WebappActivity that causes this -
I've been unable to generate a smaller repro.

This issue is solved however by making sure both the
FLAG_ACTIVITY_NEW_TASK and FLAG_ACTIVITY_NEW_DOCUMENT (which was
FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET in pre-Lollipop) have been set
on the Intent and FLAG_ONE_SHOT has been set on the PendingIntent.

Bug: 846528
Change-Id: I9602537e68b24a186961d29f4c4b1fb1ae9235b0
Reviewed-on: https://chromium-review.googlesource.com/1107631Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Bernhard Bauer <bauerb@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569286}

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

@@ -66,18 +66,26 @@ class WebappActionsNotificationManager {
     }
 
     private Notification createNotification() {
+        int intentFlags = WebappLauncherActivity.getWebappActivityIntentFlags();
+        int pendingIntentFlags = PendingIntent.FLAG_UPDATE_CURRENT | PendingIntent.FLAG_ONE_SHOT;
+
         PendingIntent focusIntent = PendingIntent.getActivity(mWebappActivity, 0,
-                new Intent(mWebappActivity, mWebappActivity.getClass()).setAction(ACTION_FOCUS),
-                PendingIntent.FLAG_UPDATE_CURRENT);
+                new Intent(mWebappActivity, mWebappActivity.getClass())
+                        .setAction(ACTION_FOCUS)
+                        .setFlags(intentFlags),
+                pendingIntentFlags);
 
         PendingIntent openInChromeIntent = PendingIntent.getActivity(mWebappActivity, 0,
                 new Intent(mWebappActivity, mWebappActivity.getClass())
-                        .setAction(ACTION_OPEN_IN_CHROME),
-                PendingIntent.FLAG_UPDATE_CURRENT);
+                        .setAction(ACTION_OPEN_IN_CHROME)
+                        .setFlags(intentFlags),
+                pendingIntentFlags);
 
         PendingIntent shareIntent = PendingIntent.getActivity(mWebappActivity, 0,
-                new Intent(mWebappActivity, mWebappActivity.getClass()).setAction(ACTION_SHARE),
-                PendingIntent.FLAG_UPDATE_CURRENT);
+                new Intent(mWebappActivity, mWebappActivity.getClass())
+                        .setAction(ACTION_SHARE)
+                        .setFlags(intentFlags),
+                pendingIntentFlags);
 
         return NotificationBuilderFactory
                 .createChromeNotificationBuilder(

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

@@ -212,6 +212,14 @@ public class WebappLauncherActivity extends Activity {
         // Activity.
         launchIntent.setAction(Intent.ACTION_VIEW);
         launchIntent.setData(Uri.parse(WebappActivity.WEBAPP_SCHEME + "://" + info.id()));
+        launchIntent.setFlags(getWebappActivityIntentFlags());
+        return launchIntent;
+    }
+
+    /**
+     * Returns the set of Intent flags required to correctly launch a WebappActivity.
+     */
+    public static int getWebappActivityIntentFlags() {
         // Setting FLAG_ACTIVITY_CLEAR_TOP handles 2 edge cases:
         // - If a legacy PWA is launching from a notification, we want to ensure that the URL being
         // launched is the URL in the intent. If a paused WebappActivity exists for this id,
@@ -222,10 +230,14 @@ public class WebappLauncherActivity extends Activity {
         // clicks a link to takes them back to the scope of a WebAPK, we want to destroy the
         // CustomTabActivity activity and go back to the WebAPK activity. It is intentional that
         // Custom Tab will not be reachable with a back button.
-        launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
+
+        // In addition FLAG_ACTIVITY_NEW_DOCUMENT is required otherwise on Samsung Lollipop devices
+        // an Intent to an existing top Activity (such as sent from the Webapp Actions Notification)
+        // will trigger a new WebappActivity to be launched and onCreate called instead of
+        // onNewIntent of the existing WebappActivity being called.
+        return Intent.FLAG_ACTIVITY_NEW_TASK
                 | ApiCompatibilityUtils.getActivityNewDocumentFlag()
-                | Intent.FLAG_ACTIVITY_CLEAR_TOP);
-        return launchIntent;
+                | Intent.FLAG_ACTIVITY_CLEAR_TOP;
     }
 
     /**