📰 Add visibility change triggers for bottom sheet content

chrome/android/java/src/org/chromium/chrome/browser/widget/bottomsheet/BottomSheet.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.animation.Animator;
 import android.animation.AnimatorListenerAdapter;
 import android.animation.AnimatorSet;
 import android.animation.ObjectAnimator;
@@ skipping 333 matching lines @@
 
             if (!wasOpenBeforeSwipe && mIsSheetOpen) {
                 mMetrics.recordSheetOpenReason(BottomSheetMetrics.OPENED_BY_SWIPE);
             }
 
             return true;
         }
     }
 
     /**
+     * Returns whether the provided bottom sheet state is in one of the stable open or closed
+     * states: {@link #SHEET_STATE_FULL}, {@link #SHEET_STATE_PEEK} or {@link #SHEET_STATE_HALF}
+     * @param sheetState A {@link SheetState} to test.
+     */
+    public static boolean isStateStable(@SheetState int sheetState) {
+        switch (sheetState) {
+            case SHEET_STATE_PEEK:
+            case SHEET_STATE_HALF:
+            case SHEET_STATE_FULL:
+                return true;
+            case SHEET_STATE_NONE:
+                assert false; // Should never be tested, internal only value.

[mdjones, 2017/05/09 17:20:15]

nit: make "assert false;" the default. This is what we do for other switch
statements. So:

case SHEET_STATE_NONE:
default:
    assert false;

[dgn, 2017/05/11 17:23:06]

Done.

+            case SHEET_STATE_SCROLLING:
+            default:
+                return false;
+        }
+    }
+
+    /**
      * Constructor for inflation from XML.
      * @param context An Android context.
      * @param atts The XML attributes.
      */
     public BottomSheet(Context context, AttributeSet atts) {
         super(context, atts);
 
         mFullHeightDistanceFromTop =
                 getResources().getDimensionPixelSize(R.dimen.chrome_home_full_height_from_top);
 
@@ skipping 792 matching lines @@
                 getContext(), mControlContainer, R.string.bottom_sheet_help_bubble_message);
         int inset = getContext().getResources().getDimensionPixelSize(
                 R.dimen.bottom_sheet_help_bubble_inset);
         helpBubble.setInsetPx(0, inset, 0, inset);
         helpBubble.setDismissOnTouchInteraction(true);
         helpBubble.show();
 
         preferences.edit().putBoolean(BOTTOM_SHEET_HELP_BUBBLE_SHOWN, true).apply();
     }
 }