Inline AppHooks#createMultiWindowUtils

The MultiWindowUtils implementation was upstreamed in
crbug.com/805938, so it no longer needs to reside in AppHooks.

Bug: 1098518
Change-Id: Iabee2370748dfa678919d9721aff10366d3e03ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2261793Reviewed-by: Matthew Jones <mdjones@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Natalie Chouinard <chouinard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#782552}

chrome/android/java/src/org/chromium/chrome/browser/AppHooks.java

@@ -32,7 +32,6 @@ import org.chromium.chrome.browser.init.ProcessInitializationHandler;
 import org.chromium.chrome.browser.instantapps.InstantAppsHandler;
 import org.chromium.chrome.browser.locale.LocaleManager;
 import org.chromium.chrome.browser.metrics.VariationsSession;
-import org.chromium.chrome.browser.multiwindow.MultiWindowUtils;
 import org.chromium.chrome.browser.offlinepages.CCTRequestStatus;
 import org.chromium.chrome.browser.omaha.RequestGenerator;
 import org.chromium.chrome.browser.partnerbookmarks.PartnerBookmark;
@@ -192,13 +191,6 @@ public abstract class AppHooks {
         return null;
     }
 
-    /**
-     * @return An instance of MultiWindowUtils to be installed as a singleton.
-     */
-    public MultiWindowUtils createMultiWindowUtils() {
-        return new MultiWindowUtils();
-    }
-
     /**
      * @return An instance of RequestGenerator to be used for Omaha XML creation.  Will be null if
      *         a generator is unavailable.

chrome/android/java/src/org/chromium/chrome/browser/multiwindow/MultiWindowUtils.java

@@ -25,7 +25,6 @@ import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.ApplicationStatus.ActivityStateListener;
 import org.chromium.base.IntentUtils;
-import org.chromium.chrome.browser.AppHooks;
 import org.chromium.chrome.browser.ChromeTabbedActivity;
 import org.chromium.chrome.browser.ChromeTabbedActivity2;
 import org.chromium.chrome.browser.IntentHandler;
@@ -45,7 +44,7 @@ import java.util.List;
  */
 public class MultiWindowUtils implements ActivityStateListener {
     // getInstance() is called early in start-up, so there is not point in lazily initializing it.
-    private static final MultiWindowUtils sInstance = AppHooks.get().createMultiWindowUtils();
+    private static final MultiWindowUtils sInstance = new MultiWindowUtils();
 
     // Used to keep track of whether ChromeTabbedActivity2 is running. A tri-state Boolean is
     // used in case both activities die in the background and MultiWindowUtils is recreated.
@@ -53,6 +52,8 @@ public class MultiWindowUtils implements ActivityStateListener {
     private WeakReference<ChromeTabbedActivity> mLastResumedTabbedActivity;
     private boolean mIsInMultiWindowModeForTesting;
 
+    private MultiWindowUtils() {}
+
     /**
      * Returns the singleton instance of MultiWindowUtils.
      */