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.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.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
 /**
  * A class for keeping track of common data associated with showing photos in
  * the photo picker, for example the RecyclerView and the bitmap caches.
  */
 public class PickerCategoryView extends RelativeLayout
         implements FileEnumWorkerTask.FilesEnumeratedCallback, RecyclerView.RecyclerListener,
                    DecoderServiceHost.ServiceReadyCallback, View.OnClickListener {
@@ skipping 49 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;
 
+    // A list of files to use for testing (instead of reading files on disk).
+    private static List<PickerBitmap> sTestFiles;
+
     public PickerCategoryView(Context context) {
         super(context);
         postConstruction(context);
     }
 
     /**
      * A helper function for initializing the PickerCategoryView.
      * @param context The context to use.
      */
     @SuppressWarnings("unchecked") // mSelectableListLayout
@@ skipping 175 matching lines @@
         // Make sure columns and padding are either both even or both odd.
         if (((mColumns % 2) == 0) != ((mPadding % 2) == 0)) {
             mPadding++;
         }
     }
 
     /**
      * Asynchronously enumerates bitmaps on disk.
      */
     private void enumerateBitmaps() {
+        if (sTestFiles != null) {
+            filesEnumeratedCallback(sTestFiles);
+            return;
+        }
+
         if (mWorkerTask != null) {
             mWorkerTask.cancel(true);
         }
 
         mWorkerTask =
                 new FileEnumWorkerTask(this, new MimeTypeFileFilter(Arrays.asList("image/*")));
         mWorkerTask.execute();
     }
 
     /**
@@ skipping 39 matching lines @@
 
                 if (position < mSpanCount) {
                     top = mSpacing;
                 }
                 bottom = mSpacing;
             }
 
             outRect.set(left, top, right, bottom);
         }
     }
+
+    /** Sets a list of files to use as data for the dialog. For testing use only. */
+    @VisibleForTesting
+    public static void setTestFiles(List<PickerBitmap> testFiles) {
+        sTestFiles = new ArrayList<>(testFiles);
+    }
+
+    @VisibleForTesting
+    public SelectionDelegate<PickerBitmap> getSelectionDelegateForTesting() {
+        return mSelectionDelegate;
+    }
 }