cc: Refactor SkipImageCanvas and create it during playback.

cc/playback/skip_image_canvas.cc

+// Copyright 2016 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.
+
+#include "cc/playback/skip_image_canvas.h"
+
+#include "third_party/skia/include/core/SkShader.h"
+
+namespace cc {
+
+SkipImageCanvas::SkipImageCanvas(SkCanvas* canvas)
+    : SkPaintFilterCanvas(canvas) {}
+
+bool SkipImageCanvas::onFilter(SkTCopyOnFirstWrite<SkPaint>* paint,
+                               Type type) const {
+  if (type == kBitmap_Type)
+    return false;
+
+  SkShader* shader = (*paint) ? (*paint)->getShader() : nullptr;
+  return !shader || !shader->isABitmap();
+}
+
+void SkipImageCanvas::onDrawPicture(const SkPicture* picture,
+                                    const SkMatrix* matrix,
+                                    const SkPaint* paint) {
+  SkTCopyOnFirstWrite<SkPaint> filteredPaint(paint);
+
+  // To filter nested draws, we must unfurl pictures at this stage.
+  if (onFilter(&filteredPaint, kPicture_Type))
+    SkCanvas::onDrawPicture(picture, matrix, filteredPaint);
+}
+
+}  // namespace cc