Make downloaded WebAPK world readable

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

 // Copyright 2016 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.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
@@ skipping 19 matching lines @@
      * @return True if the install was started. A "true" return value does not guarantee that the
      *         install succeeds.
      */
     @CalledByNative
     static boolean installAsyncFromNative(String filePath, String packageName) {
         if (!installingFromUnknownSourcesAllowed()) {
             Log.e(TAG,
                     "WebAPK install failed because installation from unknown sources is disabled.");
             return false;
         }
-        if (!new File(filePath).exists()) {
-            return false;
-        }
         Intent intent = new Intent(Intent.ACTION_VIEW);
         Uri fileUri = Uri.fromFile(new File(filePath));
         intent.setDataAndType(fileUri, "application/vnd.android.package-archive");
         intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         try {
             ContextUtils.getApplicationContext().startActivity(intent);
         } catch (ActivityNotFoundException e) {
             return false;
         }
         return true;
     }
 
     /**
      * Returns whether the user has enabled installing apps from sources other than the Google Play
      * Store.
      */
     private static boolean installingFromUnknownSourcesAllowed() {
         Context context = ContextUtils.getApplicationContext();
         try {
             return Settings.Secure.getInt(
                            context.getContentResolver(), Settings.Secure.INSTALL_NON_MARKET_APPS)
                     == 1;
         } catch (Settings.SettingNotFoundException e) {
             return false;
         }
     }
 }