[Home] Remove BottomSheetObservers that are no longer used

chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsBottomSheetContent.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.suggestions;
 
 import android.annotation.SuppressLint;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.OnScrollListener;
 import android.view.LayoutInflater;
@@ skipping 11 matching lines @@
 import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
 import org.chromium.chrome.browser.offlinepages.OfflinePageBridge;
 import org.chromium.chrome.browser.omnibox.LocationBar;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.snackbar.SnackbarManager;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.chrome.browser.widget.FadingShadow;
 import org.chromium.chrome.browser.widget.FadingShadowView;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheet;
 import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetContentController;
+import org.chromium.chrome.browser.widget.bottomsheet.BottomSheetObserver;
 import org.chromium.chrome.browser.widget.bottomsheet.EmptyBottomSheetObserver;
 import org.chromium.chrome.browser.widget.displaystyle.UiConfig;
 
 /**
  * Provides content to be displayed inside of the Home tab of bottom sheet.
  *
  * TODO(dgn): If the bottom sheet view is not recreated across tab changes, it will have to be
  * notified of it, at least when it is pulled up on the new tab.
  */
 public class SuggestionsBottomSheetContent implements BottomSheet.BottomSheetContent {
     private static SuggestionsSource sSuggestionsSourceForTesting;
     private static SuggestionsMetricsReporter sMetricsReporterForTesting;
 
     private final View mView;
     private final FadingShadowView mShadowView;
     private final SuggestionsRecyclerView mRecyclerView;
     private final ContextMenuManager mContextMenuManager;
     private final SuggestionsUiDelegateImpl mSuggestionsManager;
     private final TileGroup.Delegate mTileGroupDelegate;
+    private final BottomSheet mBottomSheet;
+    private final BottomSheetObserver mBottomSheetObserver;
 
     public SuggestionsBottomSheetContent(final ChromeActivity activity, final BottomSheet sheet,
             TabModelSelector tabModelSelector, SnackbarManager snackbarManager) {
         Profile profile = Profile.getLastUsedProfile();
         SuggestionsNavigationDelegate navigationDelegate =
                 new SuggestionsNavigationDelegateImpl(activity, profile, sheet, tabModelSelector);
         mTileGroupDelegate = new TileGroupDelegateImpl(
                 activity, profile, tabModelSelector, navigationDelegate, snackbarManager);
         mSuggestionsManager = createSuggestionsDelegate(profile, navigationDelegate, sheet);
 
@@ skipping 18 matching lines @@
         });
 
         UiConfig uiConfig = new UiConfig(mRecyclerView);
 
         final NewTabPageAdapter adapter = new NewTabPageAdapter(mSuggestionsManager,
                 /* aboveTheFoldView = */ null, uiConfig, OfflinePageBridge.getForProfile(profile),
                 mContextMenuManager, mTileGroupDelegate);
         mRecyclerView.init(uiConfig, mContextMenuManager, adapter);
 
         final SuggestionsSource suggestionsSource = mSuggestionsManager.getSuggestionsSource();
-        activity.getBottomSheet().addObserver(new EmptyBottomSheetObserver() {
+        mBottomSheetObserver = new EmptyBottomSheetObserver() {
             @Override
             public void onSheetOpened() {
                 mRecyclerView.scrollTo(0, 0);
 
                 // TODO(https://crbug.com/689962) Ensure this call does not discard all suggestions
                 // every time the sheet is opened.
                 adapter.refreshSuggestions();
                 suggestionsSource.onNtpInitialized();
             }
-        });
+        };
+        mBottomSheet = activity.getBottomSheet();
+        mBottomSheet.addObserver(mBottomSheetObserver);
         adapter.refreshSuggestions();
         suggestionsSource.onNtpInitialized();
 
         mShadowView = (FadingShadowView) mView.findViewById(R.id.shadow);
         mShadowView.init(
                 ApiCompatibilityUtils.getColor(mView.getResources(), R.color.toolbar_shadow_color),
                 FadingShadow.POSITION_TOP);
 
         mRecyclerView.addOnScrollListener(new OnScrollListener() {
             @Override
@@ skipping 33 matching lines @@
         return false;
     }
 
     @Override
     public int getVerticalScrollOffset() {
         return mRecyclerView.computeVerticalScrollOffset();
     }
 
     @Override
     public void destroy() {
+        mBottomSheet.removeObserver(mBottomSheetObserver);
         mSuggestionsManager.onDestroy();
         mTileGroupDelegate.destroy();
     }
 
     @Override
     public int getType() {
         return BottomSheetContentController.TYPE_SUGGESTIONS;
     }
 
     public static void setSuggestionsSourceForTesting(SuggestionsSource suggestionsSource) {
@@ skipping 24 matching lines @@
             metricsReporter = sMetricsReporterForTesting;
         }
 
         SuggestionsUiDelegateImpl delegate = new SuggestionsUiDelegateImpl(
                 suggestionsSource, metricsReporter, navigationDelegate, profile, host);
         if (snippetsBridge != null) delegate.addDestructionObserver(snippetsBridge);
 
         return delegate;
     }
 }