Fixes redirects to external apps when navigating from PWA.

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

 // Copyright 2017 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.net.Uri;
+import android.os.StrictMode;
 import android.support.customtabs.CustomTabsIntent;
 
+import org.chromium.base.ContextUtils;
+import org.chromium.base.Log;
+import org.chromium.chrome.browser.IntentHandler;
+import org.chromium.chrome.browser.customtabs.CustomTabIntentDataProvider;
+import org.chromium.chrome.browser.externalnav.ExternalNavigationDelegateImpl;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.chrome.browser.tab.TabIdManager;
 import org.chromium.chrome.browser.tabmodel.AsyncTabParamsManager;
 import org.chromium.chrome.browser.tabmodel.TabModel.TabLaunchType;
 import org.chromium.chrome.browser.tabmodel.document.AsyncTabCreationParams;
 import org.chromium.chrome.browser.tabmodel.document.TabDelegate;
 
+import java.net.URISyntaxException;
+
 /**
  * Asynchronously creates Tabs for navigation originating from an installed PWA.
  *
- * This is the same as the parent class with exception of opening a Custom Tab for
- * {@code _blank} links and {@code window.open(url)} calls instead of creating a new tab in Chrome.
+ * This is the same as the parent class with exception of checking for a specialized native handlers
+ * first, and if none are found opening a Custom Tab instead of creating a new tab in Chrome.
  */
 public class WebappTabDelegate extends TabDelegate {
-    private final WebappActivity mActivity;
+    private static final String TAG = "WebappTabDelegate";
 
-    public WebappTabDelegate(WebappActivity activity, boolean incognito) {
+    public WebappTabDelegate(boolean incognito) {
         super(incognito);
-        this.mActivity = activity;
     }
 
     @Override
     public void createNewTab(AsyncTabCreationParams asyncParams, TabLaunchType type, int parentId) {
+        String url = asyncParams.getLoadUrlParams().getUrl();
+        if (maybeStartExternalActivity(url)) {
+            return;
+        }
+
         int assignedTabId = TabIdManager.getInstance().generateValidId(Tab.INVALID_TAB_ID);
         AsyncTabParamsManager.add(assignedTabId, asyncParams);
 
-        CustomTabsIntent customTabIntent =
-                new CustomTabsIntent.Builder().setShowTitle(true).build();
+        Intent intent = new CustomTabsIntent.Builder().setShowTitle(true).build().intent;
+        intent.setData(Uri.parse(url));
+        intent.putExtra(CustomTabIntentDataProvider.EXTRA_SEND_TO_EXTERNAL_DEFAULT_HANDLER, true);
+        intent.putExtra(CustomTabIntentDataProvider.EXTRA_IS_OPENED_BY_CHROME, true);
+        addAsyncTabExtras(asyncParams, parentId, false /* isChromeUI */, assignedTabId, intent);
 
-        customTabIntent.intent.setPackage(mActivity.getPackageName());
-        addAsyncTabExtras(asyncParams, parentId, true, assignedTabId, customTabIntent.intent);
-        customTabIntent.launchUrl(mActivity, Uri.parse(asyncParams.getLoadUrlParams().getUrl()));
+        IntentHandler.startActivityForTrustedIntent(intent);
+    }
+
+    private boolean maybeStartExternalActivity(String url) {
+        Intent intent;
+        try {
+            intent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME);
+        } catch (URISyntaxException ex) {
+            Log.w(TAG, "Bad URI %s", url, ex);
+            return false;
+        }
+
+        // See http://crbug.com/613977 for more context.
+        StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskWrites();
+        try {
+            // Launch a native app iff there is a specialized handler for a given URL.
+            if (ExternalNavigationDelegateImpl.isPackageSpecializedHandler(null, intent)) {
+                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+                ContextUtils.getApplicationContext().startActivity(intent);
+                return true;
+            }
+        } finally {
+            StrictMode.setThreadPolicy(oldPolicy);
+        }
+
+        return false;
     }
 }