Implement the new Photo picker, part two.

chrome/android/java/src/org/chromium/chrome/browser/photo_picker/AcceptFileFilter.java

Index: chrome/android/java/src/org/chromium/chrome/browser/photo_picker/AcceptFileFilter.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/AcceptFileFilter.java b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/AcceptFileFilter.java
new file mode 100644
index 0000000000000000000000000000000000000000..a08a1ab934a6ae49885dcd9039f664673dc9bf95
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/photo_picker/AcceptFileFilter.java
@@ -0,0 +1,38 @@
+// 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.support.annotation.NonNull;
+
+import java.io.File;
+import java.io.FileFilter;
+
+/**
+ * Base class for FileFilters used when selection photos.
+ */
+public abstract class AcceptFileFilter implements FileFilter {
+    private static AcceptFileFilter sDefaultSingleton = null;
+
+    @NonNull
+    public static AcceptFileFilter getDefault() {
+        if (sDefaultSingleton == null) {
+            sDefaultSingleton = new DefaultAcceptFileFilter();
+        }
+        return sDefaultSingleton;
+    }
+
+    @NonNull
+    public static AcceptFileFilter forAttr(@NonNull String acceptAttr) {
+        return new AttrAcceptFileFilter(acceptAttr);
+    }
+
+    public abstract boolean accept(@NonNull File file);
+
+    public abstract boolean acceptsImages();
+
+    public abstract boolean acceptsVideos();
+
+    public abstract boolean acceptsOther();
+}