cc: Add some impl-side painting stub classes and APIs

cc/picture.h

+// Copyright 2012 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 CC_PICTURE_H_
+#define CC_PICTURE_H_
+
+#include "base/basictypes.h"
+#include "cc/cc_export.h"
+#include "cc/picture_record.h"
+#include "cc/scoped_ptr_vector.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/size.h"
+
+namespace cc {
+
+class CC_EXPORT Picture {
+public:
+  Picture();
+  ~Picture();
+
+  // Mark a portion of the Picture as invalid and needing to be re-recorded
+  // the next time update is called.
+  void invalidate(gfx::Rect);
+
+  // Resize the Picture, invalidating / dropping recorded pictures as necessary.
+  void resize(gfx::Size);
+
+  // Rerecord parts of the picture that are invalid.
+  void update(ContentLayerClient* painter);
+
+  // Update other with a shallow copy of this (main => compositor thread commit)
+  void pushPropertiesTo(Picture& other);
+
+  // Clone a paint-safe version of this picture (with cloned PictureRecords)

[nduca, 2012/11/08 00:49:35]

lets add this method later when we wrap our head around how to do this?

+  scoped_ptr<Picture> cloneForDrawing(gfx::Rect rect);
+
+  // Raster a subrect of this Picture into the given canvas.
+  // It's only safe to call paint on a cloned version.
+  void paint(SkCanvas* canvas, gfx::Rect rect);
+
+protected:
+  std::vector<scoped_refptr<PictureRecord> > pile_;
+  gfx::Size size_;
+
+  DISALLOW_COPY_AND_ASSIGN(Picture);
+};
+
+}  // namespace cc
+
+#endif  // CC_PICTURE_H_