Redirecting off-origin navigations in PWAs to CCT.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
index a232f04b66ad689b7d37309dd32e758ad99464f6..6d86fe2cfa7f4c3d2952793c2ff020feafe079be 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappLauncherActivity.java
@@ -196,19 +196,19 @@ public class WebappLauncherActivity extends Activity {
         launchIntent.setData(Uri.parse(WebappActivity.WEBAPP_SCHEME + "://" + info.id()));
         launchIntent.setFlags(
                 Intent.FLAG_ACTIVITY_NEW_TASK | ApiCompatibilityUtils.getActivityNewDocumentFlag());
-
-        if (!isWebApk) {
-            // If this 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,
-            // then by default it will be focused and we have no way of sending the desired URL to
-            // it (the intent is swallowed). As a workaround, set the CLEAR_TOP flag to ensure that
-            // the existing Activity is cleared and relaunched with this intent.
-            // TODO(dominickn): ideally, we want be able to route an intent to
-            // WebappActivity.onNewIntent instead of restarting the Activity.
-            if (source == ShortcutSource.NOTIFICATION) {

[pkotwicz, 2017/05/26 05:13:01]

Given that this CL was reverted (not by me!) it is worth mentioning that with
singleTop in AndroidManifest.xml for WebappActivity, this no longer causes the
webapp to be relaunched for Intent.FLAG_ACTIVITY_CLEAR_TOP for notifications.

[piotrs, 2017/05/26 05:39:31]

Done.

-                launchIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
-            }
-        }
+        // 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,
+        // then by default it will be focused and we have no way of sending the desired URL to
+        // it (the intent is swallowed). As a workaround, set the CLEAR_TOP flag to ensure that
+        // the existing Activity is cleared and relaunched with this intent.
+        // - If a WebAPK is having a CustomTabActivity on top of it in the same Task, and user
+        // 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.
+        // TODO(dominickn): ideally, we want be able to route an intent to onNewIntent() instead of
+        // restarting the Activity.
+        launchIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
         return launchIntent;
     }