Convert SkiaBitLocker to use PaintCanvas

third_party/WebKit/Source/platform/mac/GraphicsContextCanvas.h

+// Copyright (c) 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.
+
+#ifndef GraphicsContextCanvas_h
+#define GraphicsContextCanvas_h
+
+#include <ApplicationServices/ApplicationServices.h>
+
+#include "platform/PlatformExport.h"
+#include "platform/graphics/paint/PaintCanvas.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+struct SkIRect;
+
+namespace blink {
+
+// Converts a PaintCanvas temporarily to a CGContext
+class PLATFORM_EXPORT GraphicsContextCanvas {
+ public:
+  /**
+    User clip rect is an *additional* clip to be applied in addition to the
+    current state of the canvas, in *local* rather than device coordinates.
+    If no additional clipping is desired, pass in
+    SkIRect::MakeSize(canvas->getBaseLayerSize()) transformed by the inverse
+    CTM.
+   */
+  GraphicsContextCanvas(PaintCanvas*,
+                        const SkIRect& userClipRect,
+                        SkScalar bitmapScaleFactor = 1);
+  ~GraphicsContextCanvas();
+  CGContextRef cgContext();
+  bool hasEmptyClipRegion() const;
+
+ private:
+  void releaseIfNeeded();
+  SkIRect computeDirtyRect();
+
+  PaintCanvas* m_canvas;
+
+  CGContextRef m_cgContext;
+  // m_offscreen is only valid if m_useDeviceBits is false
+  SkBitmap m_offscreen;
+  SkIPoint m_bitmapOffset;
+  SkScalar m_bitmapScaleFactor;
+
+  // True if we are drawing to |m_canvas|'s backing store directly.
+  // Otherwise, the bits in |bitmap_| are our allocation and need to
+  // be copied over to |m_canvas|.
+  bool m_useDeviceBits;
+
+  // True if |bitmap_| is a dummy 1x1 bitmap allocated for the sake of creating
+  // a non-null CGContext (it is invalid to use a null CGContext), and will not
+  // be copied to |m_canvas|. This will happen if |m_canvas|'s clip region is
+  // empty.
+  bool m_bitmapIsDummy;
+};
+
+}  // namespace blink
+
+#endif  // GraphicsContextCanvas_h