Photo Picker dialog: Add a test.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/PickerCategoryView.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.photo_picker;
 
 import android.app.Activity;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.Rect;
+import android.support.annotation.Nullable;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
 import android.util.LruCache;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.Button;
 import android.widget.RelativeLayout;
 
+import org.chromium.base.VisibleForTesting;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.widget.selection.SelectableListLayout;
 import org.chromium.chrome.browser.widget.selection.SelectionDelegate;
 import org.chromium.ui.PhotoPickerListener;
 
 import java.util.Arrays;
 import java.util.List;
 
 /**
  * A class for keeping track of common data associated with showing photos in
@@ skipping 54 matching lines @@
 
     // The size of the bitmaps (equal length for width and height).
     private int mImageSize;
 
     // A worker task for asynchronously enumerating files off the main thread.
     private FileEnumWorkerTask mWorkerTask;
 
     // Whether the connection to the service has been established.
     private boolean mServiceReady;
 
-    public PickerCategoryView(Context context) {
+    public PickerCategoryView(Context context, @Nullable List<PickerBitmap> testFiles) {
         super(context);
+
+        mPickerBitmaps = testFiles;
         postConstruction(context);
     }
 
     /**
      * A helper function for initializing the PickerCategoryView.
      * @param context The context to use.
      */
     @SuppressWarnings("unchecked") // mSelectableListLayout
     private void postConstruction(Context context) {
         mContext = context;
 
         mDecoderServiceHost = new DecoderServiceHost(this);
         mDecoderServiceHost.bind(mContext);
 
-        enumerateBitmaps();
+        if (mPickerBitmaps == null) {
+            enumerateBitmaps();
+        }
 
         mSelectionDelegate = new SelectionDelegate<PickerBitmap>();
 
         View root = LayoutInflater.from(context).inflate(R.layout.photo_picker_dialog, this);
         mSelectableListLayout =
                 (SelectableListLayout<PickerBitmap>) root.findViewById(R.id.selectable_list);
 
         mPickerAdapter = new PickerAdapter(this);
         mRecyclerView = mSelectableListLayout.initializeRecyclerView(mPickerAdapter);
         PhotoPickerToolbar toolbar = (PhotoPickerToolbar) mSelectableListLayout.initializeToolbar(
@@ skipping 217 matching lines @@
 
                 if (position < mSpanCount) {
                     top = mSpacing;
                 }
                 bottom = mSpacing;
             }
 
             outRect.set(left, top, right, bottom);
         }
     }
+
+    @VisibleForTesting
+    public SelectionDelegate<PickerBitmap> getSelectionDelegateForTesting() {
+        return mSelectionDelegate;
+    }
 }