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

chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticleViewHolder.java

 // Copyright 2015 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.ntp.snippets;
 
 import android.annotation.SuppressLint;
 import android.content.res.ColorStateList;
 import android.content.res.Resources;
 import android.graphics.Bitmap;
@@ skipping 338 matching lines @@
 
             if (fileType != DownloadFilter.FILTER_IMAGE) return;
             if (mImageCallback != null) {
                 mThumbnailProvider.cancelRetrieval(mImageCallback);
                 mImageCallback = null;
             }
             mImageCallback = new FetchImageCallback(this, mArticle);
             mArticle.setThumbnailBitmap(null);
             Bitmap thumbnail = mThumbnailProvider.getThumbnail(mImageCallback);
             if (thumbnail == null || thumbnail.isRecycled()) return;
-            mArticle.setThumbnailBitmap(thumbnail);
+            mArticle.setThumbnailBitmap(mUiDelegate.getReferencePool().put(thumbnail));
             setThumbnailFromBitmap(thumbnail);
 
             return;
         }
 
         setThumbnailFromFileType(DownloadFilter.FILTER_PAGE);
     }
 
     private void setThumbnail() {
         // If there's still a pending thumbnail fetch, cancel it.
         cancelImageFetch();
 
         // mThumbnailView's visibility is modified in updateLayout().
         if (mThumbnailView.getVisibility() != View.VISIBLE) return;
-        if (mArticle.getThumbnailBitmap() != null && !mArticle.getThumbnailBitmap().isRecycled()) {
-            setThumbnailFromBitmap(mArticle.getThumbnailBitmap());
+        Bitmap thumbnail = mArticle.getThumbnailBitmap();
+        if (thumbnail != null && !thumbnail.isRecycled()) {
+            setThumbnailFromBitmap(thumbnail);
             return;
         }
 
         if (mArticle.isDownload()) {
             setDownloadThumbnail();
             return;
         }
 
         // Temporarily set placeholder and then fetch the thumbnail from a provider.
         mThumbnailView.setBackground(null);
@@ skipping 25 matching lines @@
 
         // We need to crop and scale the downloaded bitmap, as the ImageView we set it on won't be
         // able to do so when using a TransitionDrawable (as opposed to the straight bitmap).
         // That's a limitation of TransitionDrawable, which doesn't handle layers of varying sizes.
         Resources res = mThumbnailView.getResources();
         int targetSize = res.getDimensionPixelSize(R.dimen.snippets_thumbnail_size);
         Bitmap scaledThumbnail = ThumbnailUtils.extractThumbnail(
                 thumbnail, targetSize, targetSize, ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
 
         // Store the bitmap to skip the download task next time we display this snippet.
-        snippet.setThumbnailBitmap(scaledThumbnail);
+        snippet.setThumbnailBitmap(mUiDelegate.getReferencePool().put(scaledThumbnail));
 
         // Cross-fade between the placeholder and the thumbnail. We cross-fade because the incoming
         // image may have transparency and we don't want the previous image showing up behind.
         Drawable[] layers = {mThumbnailView.getDrawable(),
                 new BitmapDrawable(mThumbnailView.getResources(), scaledThumbnail)};
         TransitionDrawable transitionDrawable = new TransitionDrawable(layers);
         mThumbnailView.setScaleType(ImageView.ScaleType.CENTER_CROP);
         mThumbnailView.setBackground(null);
         mThumbnailView.setImageDrawable(transitionDrawable);
         mThumbnailView.setTint(null);
@@ skipping 153 matching lines @@
      * Callback to refresh the offline badge visibility.
      */
     public static class RefreshOfflineBadgeVisibilityCallback extends PartialBindCallback {
         @Override
         public void onResult(NewTabPageViewHolder holder) {
             assert holder instanceof SnippetArticleViewHolder;
             ((SnippetArticleViewHolder) holder).refreshOfflineBadgeVisibility();
         }
     }
 }