customtabs: Extract a redirect endpoint, and maybe connect to it.

chrome/android/java/src/org/chromium/chrome/browser/WarmupManager.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;
 
 import android.annotation.SuppressLint;
 import android.content.Context;
+import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.StrictMode;
 import android.os.SystemClock;
+import android.text.TextUtils;
 import android.view.ContextThemeWrapper;
 import android.view.InflateException;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.ViewStub;
 import android.widget.FrameLayout;
 
 import org.chromium.base.Log;
 import org.chromium.base.SysUtils;
@@ skipping 198 matching lines @@
         }
     }
 
     /** Asynchronously preconnects to a given URL if the data reduction proxy is not in use.
      *
      * @param profile The profile to use for the preconnection.
      * @param url The URL we want to preconnect to.
      */
     public void maybePreconnectUrlAndSubResources(Profile profile, String url) {
         ThreadUtils.assertOnUiThread();
-        if (!DataReductionProxySettings.getInstance().isDataReductionProxyEnabled()) {
-            // If there is already a DNS request in flight for this URL, then
-            // the preconnection will start by issuing a DNS request for the
-            // same domain, as the result is not cached. However, such a DNS
-            // request has already been sent from this class, so it is better to
-            // wait for the answer to come back before preconnecting. Otherwise,
-            // the preconnection logic will wait for the result of the second
-            // DNS request, which should arrive after the result of the first
-            // one. Note that we however need to wait for the main thread to be
-            // available in this case, since the preconnection will be sent from
-            // AsyncTask.onPostExecute(), which may delay it.
-            if (mDnsRequestsInFlight.contains(url)) {
-                // Note that if two requests come for the same URL with two
-                // different profiles, the last one will win.
-                mPendingPreconnectWithProfile.put(url, profile);
-            } else {
-                nativePreconnectUrlAndSubresources(profile, url);
-            }
+
+        Uri uri = Uri.parse(url);
+        if (uri == null) return;
+        // HTTP connections will not be used when the data reduction proxy is enabled.
+        if (DataReductionProxySettings.getInstance().isDataReductionProxyEnabled()
+                && TextUtils.equals(UrlConstants.HTTP_SCHEME, uri.normalizeScheme().getScheme())) {

[Bernhard Bauer, 2017/07/10 12:13:44]

Nit: TextUtils.equals feels like overkill here -- both are strings, and you know
that HTTP_SCHEME is non-null.

[Benoit L, 2017/07/10 12:35:38]

Done.

+            return;
+        }
+
+        // If there is already a DNS request in flight for this URL, then the preconnection will
+        // start by issuing a DNS request for the same domain, as the result is not cached. However,
+        // such a DNS request has already been sent from this class, so it is better to wait for the
+        // answer to come back before preconnecting. Otherwise, the preconnection logic will wait
+        // for the result of the second DNS request, which should arrive after the result of the
+        // first one. Note that we however need to wait for the main thread to be available in this
+        // case, since the preconnection will be sent from AsyncTask.onPostExecute(), which may
+        // delay it.
+        if (mDnsRequestsInFlight.contains(url)) {
+            // Note that if two requests come for the same URL with two different profiles, the last
+            // one will win.
+            mPendingPreconnectWithProfile.put(url, profile);
+        } else {
+            nativePreconnectUrlAndSubresources(profile, url);
         }
     }
 
     /**
      * Creates and initializes a spare WebContents, to be used in a subsequent navigation.
      *
      * This creates a renderer that is suitable for any navigation. It can be picked up by any tab.
      * Can be called multiple times, and must be called from the UI thread.
      * Note that this is a no-op on low-end devices.
      */
@@ skipping 50 matching lines @@
         mObserver = null;
     }
 
     private static void recordWebContentsStatus(int status) {
         RecordHistogram.recordEnumeratedHistogram(
                 WEBCONTENTS_STATUS_HISTOGRAM, status, WEBCONTENTS_STATUS_COUNT);
     }
 
     private static native void nativePreconnectUrlAndSubresources(Profile profile, String url);
 }