Enable spare RenderProcessHost to be preinitialized.

chrome/android/java/src/org/chromium/chrome/browser/omnibox/AutocompleteController.java

 // Copyright 2014 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.omnibox;
 
 import android.os.Bundle;
 import android.text.TextUtils;
 
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.WarmupManager;
 import org.chromium.chrome.browser.omnibox.OmniboxSuggestion.MatchClassification;
 import org.chromium.chrome.browser.omnibox.VoiceSuggestionProvider.VoiceResult;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.content_public.browser.WebContents;
 
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * Bridge to the native AutocompleteControllerAndroid.
@@ skipping 124 matching lines @@
      *
      * @param profile The profile to use for starting the AutocompleteController.
      * @param omniboxText The text displayed in the omnibox.
      * @param url The url of the currently loaded web page.
      * @param focusedFromFakebox Whether the user entered the omnibox by tapping the fakebox on the
      *                           native NTP. This should be false on all other pages.
      */
     public void startZeroSuggest(Profile profile, String omniboxText, String url,
             boolean focusedFromFakebox) {
         if (profile == null || TextUtils.isEmpty(url)) return;
+
+        WarmupManager.getInstance().createSpareRenderProcessHost(profile);

[Charlie Reis, 2017/06/25 23:48:27]

Worth having a comment here saying how the spare process will be used (i.e., for
either subsequent ServiceWorkers or navigations likely to result from the
upcoming search?).

[mattcary, 2017/06/26 14:45:05]

Done.

+
         mNativeAutocompleteControllerAndroid = nativeInit(profile);
         if (mNativeAutocompleteControllerAndroid != 0) {
             if (mUseCachedZeroSuggestResults) mWaitingForSuggestionsToCache = true;
             nativeOnOmniboxFocused(mNativeAutocompleteControllerAndroid, omniboxText, url,
                     focusedFromFakebox);
         }
     }
 
     /**
      * Stops generating autocomplete suggestions for the currently specified text from
@@ skipping 197 matching lines @@
      * @param query The query to be expanded into a fully qualified URL if appropriate.
      * @return The fully qualified URL or null.
      */
     public static native String nativeQualifyPartialURLQuery(String query);
 
     /**
      * Sends a zero suggest request to the server in order to pre-populate the result cache.
      */
     public static native void nativePrefetchZeroSuggestResults();
 }