[Payments] Implement openWindow for service worker based payment handler

chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
index 14bb1b66e4945542f79a51509180ea252c8b62ad..0118078159bfb075dfb8fe5a0ced28ba635c2842 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/CustomTabActivity.java
@@ -45,6 +45,7 @@ import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.IntentHandler;
 import org.chromium.chrome.browser.IntentHandler.ExternalAppId;
 import org.chromium.chrome.browser.KeyboardShortcuts;
+import org.chromium.chrome.browser.ServiceTabLauncher;
 import org.chromium.chrome.browser.UrlConstants;
 import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.WebContentsFactory;
@@ -747,6 +748,13 @@ public class CustomTabActivity extends ChromeActivity {
         params.setTransitionType(IntentHandler.getTransitionTypeFromIntent(intent,
                 PageTransition.LINK | PageTransition.FROM_API));
         tab.loadUrl(params);
+
+        // Notify ServiceTabLauncher if this is an asynchronous tab launch.
+        if (intent.hasExtra(ServiceTabLauncher.LAUNCH_REQUEST_ID_EXTRA)) {
+            ServiceTabLauncher.onWebContentsForRequestAvailable(
+                    intent.getIntExtra(ServiceTabLauncher.LAUNCH_REQUEST_ID_EXTRA, 0),
+                    tab.getWebContents());

[Yusuf, 2017/05/31 18:28:59]

should this be in finishNativeInitialization? Doesn't seem very related with
loading, but looks more like a post tab initialization task that is needed only
once per custom tab.

[gogerald1, 2017/05/31 19:49:53]

Done.

+        }
     }
 
     @Override