Add PictureRecorder for sp/non-sp recording without an existing context

Source/platform/graphics/paint/SkPictureBuilder.h

+// Copyright 2015 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.
+
+#ifndef SkPictureBuilder_h
+#define SkPictureBuilder_h
+
+#include "platform/RuntimeEnabledFeatures.h"
+#include "platform/graphics/GraphicsContext.h"
+#include "platform/graphics/paint/DisplayItemList.h"
+#include "wtf/OwnPtr.h"
+
+namespace blink {
+
+// When slimming paint ships we can remove this SkPicture abstraction and
+// rely on DisplayItemList here.
+class SkPictureBuilder {
+    WTF_MAKE_NONCOPYABLE(SkPictureBuilder);
+    STACK_ALLOCATED();
+public:
+    SkPictureBuilder(const FloatRect& bounds)
+    {
+        if (RuntimeEnabledFeatures::slimmingPaintEnabled()) {
+            m_displayItemList = DisplayItemList::create();
+            m_context = adoptPtr(new GraphicsContext(m_displayItemList.get()));
+        } else {
+            m_context = GraphicsContext::deprecatedCreateWithCanvas(nullptr);
+        }
+        m_context->beginRecording(bounds);
+    }
+
+    GraphicsContext& context() { return *m_context; }
+
+    PassRefPtr<const SkPicture> endRecording()
+    {
+        if (m_displayItemList)
+            m_displayItemList->commitNewDisplayItemsAndReplay(*m_context);
+        return m_context->endRecording();
+    }
+
+private:
+    OwnPtr<DisplayItemList> m_displayItemList;
+    OwnPtr<GraphicsContext> m_context;
+};
+
+} // namespace blink
+
+#endif // SkPictureBuilder_h