[Suggestions UI] Drop Bitmap references from articles under memory pressure.

chrome/android/java/src/org/chromium/chrome/browser/suggestions/SuggestionsUiDelegateImpl.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.support.annotation.Nullable;
 
+import org.chromium.base.DiscardableReferencePool;
 import org.chromium.chrome.browser.NativePageHost;
 import org.chromium.chrome.browser.favicon.FaviconHelper;
 import org.chromium.chrome.browser.favicon.FaviconHelper.FaviconImageCallback;
 import org.chromium.chrome.browser.favicon.FaviconHelper.IconAvailabilityCallback;
 import org.chromium.chrome.browser.favicon.LargeIconBridge;
 import org.chromium.chrome.browser.favicon.LargeIconBridge.LargeIconCallback;
 import org.chromium.chrome.browser.ntp.snippets.SuggestionsSource;
 import org.chromium.chrome.browser.profiles.Profile;
 
 import java.util.ArrayList;
 import java.util.List;
 
 /**
  * {@link SuggestionsUiDelegate} implementation.
  */
 public class SuggestionsUiDelegateImpl implements SuggestionsUiDelegate {
     private final List<DestructionObserver> mDestructionObservers = new ArrayList<>();
     private final SuggestionsSource mSuggestionsSource;
     private final SuggestionsRanker mSuggestionsRanker;
     private final SuggestionsEventReporter mSuggestionsEventReporter;
     private final SuggestionsNavigationDelegate mSuggestionsNavigationDelegate;
 
     private final Profile mProfile;
 
     private final NativePageHost mHost;
 
+    private final DiscardableReferencePool mReferencePool;
+
     private FaviconHelper mFaviconHelper;
     private LargeIconBridge mLargeIconBridge;
 
     private boolean mIsDestroyed;
 
     public SuggestionsUiDelegateImpl(SuggestionsSource suggestionsSource,
             SuggestionsEventReporter eventReporter,
-            SuggestionsNavigationDelegate navigationDelegate, Profile profile,
-            NativePageHost host) {
+            SuggestionsNavigationDelegate navigationDelegate, Profile profile, NativePageHost host,
+            DiscardableReferencePool referencePool) {
         mSuggestionsSource = suggestionsSource;
         mSuggestionsRanker = new SuggestionsRanker();
         mSuggestionsEventReporter = eventReporter;
         mSuggestionsNavigationDelegate = navigationDelegate;
 
         mProfile = profile;
         mHost = host;
+        mReferencePool = referencePool;
     }
 
     @Override
     public void getLocalFaviconImageForURL(
             String url, int size, FaviconImageCallback faviconCallback) {
         if (mIsDestroyed) return;
         getFaviconHelper().getLocalFaviconImageForURL(mProfile, url, size, faviconCallback);
     }
 
     @Override
@@ skipping 29 matching lines @@
         return mSuggestionsEventReporter;
     }
 
     @Nullable
     @Override
     public SuggestionsNavigationDelegate getNavigationDelegate() {
         return mSuggestionsNavigationDelegate;
     }
 
     @Override
+    public DiscardableReferencePool getReferencePool() {
+        return mReferencePool;
+    }
+
+    @Override
     public void addDestructionObserver(DestructionObserver destructionObserver) {
         mDestructionObservers.add(destructionObserver);
     }
 
     @Override
     public boolean isVisible() {
         return mHost.isVisible();
     }
 
     /** Invalidates the delegate and calls the registered destruction observers. */
@@ skipping 26 matching lines @@
     /**
      * Utility method to lazily create the {@link LargeIconBridge}, and avoid unnecessary native
      * calls in tests.
      */
     private LargeIconBridge getLargeIconBridge() {
         assert !mIsDestroyed;
         if (mLargeIconBridge == null) mLargeIconBridge = new LargeIconBridge(mProfile);
         return mLargeIconBridge;
     }
 }