[NTP Snippets] 📷 Add placeholders and start caching thumbnails

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

Index: chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java
index 7d99986fe6f1df09a45022777b0ac8074a927bc2..f4c81f84d07acc219a0e4f0fc67260460467d352 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/ntp/snippets/SnippetArticle.java
@@ -3,27 +3,14 @@
 // found in the LICENSE file.
 package org.chromium.chrome.browser.ntp.snippets;
 
-import android.graphics.drawable.Drawable;
-import android.os.AsyncTask;
-import android.view.View;
-import android.widget.ImageView;
+import android.graphics.Bitmap;
 
-import org.chromium.base.Log;
-import org.chromium.base.StreamUtil;
 import org.chromium.chrome.browser.ntp.cards.NewTabPageListItem;
 
-import java.io.IOException;
-import java.io.InputStream;
-import java.net.MalformedURLException;
-import java.net.URL;
-
 /**
  * Represents the data for an article card on the NTP.
  */
 public class SnippetArticle implements NewTabPageListItem {
-    private static final String TAG = "SnippetArticle";
-
-    private static final int FADE_IN_ANIMATION_TIME_MS = 300;
 
     public final String mTitle;
     public final String mPublisher;
@@ -33,54 +20,8 @@
     public final long mTimestamp;
     public final int mPosition;
 
-    private ThumbnailRenderingTask mThumbnailRenderingTask;
-
-    // Async task to create the thumbnail from a URL
-    // TODO(maybelle): This task to retrieve the thumbnail from the web is temporary while
-    // we are prototyping this feature for clank. For the real production feature, we
-    // will likely have to download/decode the thumbnail on the native side.
-    private static class ThumbnailRenderingTask extends AsyncTask<String, Void, Drawable> {
-        private ImageView mThumbnailView;
-
-        ThumbnailRenderingTask(ImageView thumbnailView) {
-            mThumbnailView = thumbnailView;
-
-            // The view might be already holding the thumbnail from another snippet, as the view
-            // is recycled. We start by hiding it to avoid having a stale image be displayed while
-            // the new one is being downloaded.
-            mThumbnailView.setVisibility(View.INVISIBLE);
-        }
-
-        @Override
-        protected Drawable doInBackground(String... params) {
-            if (params[0].isEmpty()) return null;
-            InputStream is = null;
-            try {
-                is = (InputStream) new URL(params[0]).getContent();
-                return Drawable.createFromStream(is, "thumbnail");
-            } catch (MalformedURLException e) {
-                Log.e(TAG, "Could not get image thumbnail due to malformed URL", e);
-            } catch (IOException e) {
-                Log.e(TAG, "Could not get image thumbnail", e);
-            } finally {
-                StreamUtil.closeQuietly(is);
-            }
-            return null;
-        }
-
-        @Override
-        protected void onPostExecute(Drawable thumbnail) {
-            if (thumbnail == null) {
-                mThumbnailView.setVisibility(View.GONE);
-            } else {
-                // Fade in the image thumbnail
-                mThumbnailView.setImageDrawable(thumbnail);
-                mThumbnailView.setVisibility(View.VISIBLE);
-                mThumbnailView.setAlpha(0f);
-                mThumbnailView.animate().alpha(1f).setDuration(FADE_IN_ANIMATION_TIME_MS);
-            }
-        }
-    }
+    /** Bitmap of the thumbnail, fetched lazily, when the RecyclerView wants to show the snippet. */
+    private Bitmap mThumbnailBitmap;
 
     /**
      * Creates a SnippetArticle object that will hold the data
@@ -109,15 +50,15 @@ public int getType() {
     }
 
     /**
-     * Retrieves this SnippetArticle's thumbnail asynchronously and sets it onto the given
-     * ImageView.
-     *
-     * @param view The ImageView to set the thumbnail onto.
+     * Returns this article's tumbnail as a {@link Bitmap}. Can return {@code null} as it is
+     * initially unset.
      */
-    public void setThumbnailOnView(ImageView view) {
-        if (mThumbnailRenderingTask != null) mThumbnailRenderingTask.cancel(true);
+    Bitmap getThumbnailBitmap() {
+        return mThumbnailBitmap;
+    }
 
-        mThumbnailRenderingTask = new ThumbnailRenderingTask(view);
-        mThumbnailRenderingTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, mThumbnailUrl);
+    /** Sets the tumbnail bitmap for this article. */
+    void setThumbnailBitmap(Bitmap bitmap) {
+        mThumbnailBitmap = bitmap;
     }
 }