Fix an issue that external protocol in subframes are not handled on Android

chrome/android/java/src/org/chromium/chrome/browser/externalnav/ExternalNavigationHandler.java

 // Copyright 2015 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.externalnav;
 
 import android.app.Activity;
 import android.content.ActivityNotFoundException;
 import android.content.ComponentName;
 import android.content.Intent;
@@ skipping 340 matching lines @@
     /**
      * Clobber the current tab with fallback URL.
      *
      * @param browserFallbackUrl The fallback URL.
      * @param params The external navigation params.
      * @return {@link OverrideUrlLoadingResult} if the tab was clobbered, or we launched an
      *         intent.
      */
     private OverrideUrlLoadingResult clobberCurrentTabWithFallbackUrl(
             String browserFallbackUrl, ExternalNavigationParams params) {
+        if (!params.isMainFrame()) {
+            // For subframes, we don't support fallback url for now.
+            // http://crbug.com/364522.
+            return OverrideUrlLoadingResult.NO_OVERRIDE;
+        }
         // NOTE: any further redirection from fall-back URL should not override URL loading.
         // Otherwise, it can be used in chain for fingerprinting multiple app installation
         // status in one shot. In order to prevent this scenario, we notify redirection
         // handler that redirection from the current navigation should stay in Chrome.
         if (params.getRedirectHandler() != null) {
             params.getRedirectHandler().setShouldNotOverrideUrlLoadingUntilNewUrlLoading();
         }
         return mDelegate.clobberCurrentTab(
                 browserFallbackUrl, params.getReferrerUrl(), params.getTab());
     }
 
     /**
      * @return Whether the |url| could be handled by an external application on the system.
      */
     public boolean canExternalAppHandleUrl(String url) {
         if (url.startsWith(SCHEME_WTAI_MC)) return true;
         try {
             Intent intent = Intent.parseUri(url, Intent.URI_INTENT_SCHEME);
             return intent.getPackage() != null || mDelegate.canResolveActivity(intent);
         } catch (URISyntaxException ex) {
             // Ignore the error.
         }
         return false;
     }
 }