🏠 Add expand button and flag to enable it

chrome/android/java/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheetMetrics.java

 // Copyright 2017 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.widget.bottomsheet;
 
 import android.support.annotation.IntDef;
 
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheet.BottomSheetContent;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.concurrent.TimeUnit;
 
 /**
  * Records user actions and histograms related to the {@link BottomSheet}.
  */
 public class BottomSheetMetrics extends EmptyBottomSheetObserver {
     /**
      * The different ways that the bottom sheet can be opened. This is used to back a UMA
      * histogram and should therefore be treated as append-only.
      */
-    @IntDef({OPENED_BY_SWIPE, OPENED_BY_OMNIBOX_FOCUS, OPENED_BY_NEW_TAB_CREATION})
+    @IntDef({OPENED_BY_SWIPE, OPENED_BY_OMNIBOX_FOCUS, OPENED_BY_NEW_TAB_CREATION,
+            OPENED_BY_EXPAND_BUTTON})
     @Retention(RetentionPolicy.SOURCE)
     public @interface SheetOpenReason {}
     public static final int OPENED_BY_SWIPE = 0;
     public static final int OPENED_BY_OMNIBOX_FOCUS = 1;
     public static final int OPENED_BY_NEW_TAB_CREATION = 2;
-    private static final int OPENED_BY_BOUNDARY = 3;
+    public static final int OPENED_BY_EXPAND_BUTTON = 3;
+    private static final int OPENED_BY_BOUNDARY = 4;
 
     /** Whether the sheet is currently open. */
     private boolean mIsSheetOpen;
 
     /** The last {@link BottomSheetContent} that was displayed. */
     private BottomSheetContent mLastContent;
 
     /** When this class was created. Used as a proxy for when the app was started. */
     private long mCreationTime;
 
@@ skipping 72 matching lines @@
 
     /**
      * Records the reason the sheet was opened.
      * @param reason The {@link SheetOpenReason} that caused the bottom sheet to open.
      */
     public void recordSheetOpenReason(@SheetOpenReason int reason) {
         RecordHistogram.recordEnumeratedHistogram(
                 "Android.ChromeHome.OpenReason", reason, OPENED_BY_BOUNDARY);
     }
 }