Revert of Delete Mac & Cairo skia::BitmapPlatformDevice impls

skia/ext/bitmap_platform_device_mac.h

+// Copyright (c) 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 SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_
+#define SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_
+
+#include <stdint.h>
+
+#include "base/compiler_specific.h"
+#include "base/macros.h"
+#include "skia/ext/platform_device.h"
+
+namespace skia {
+
+// A device is basically a wrapper around SkBitmap that provides a surface for
+// SkCanvas to draw into. Our device provides a surface CoreGraphics can also
+// write to. BitmapPlatformDevice creates a bitmap using
+// CGCreateBitmapContext() in a format that Skia supports and can then use this
+// to draw text into, etc. This pixel data is provided to the bitmap that the
+// device contains so that it can be shared.
+//
+// The device owns the pixel data, when the device goes away, the pixel data
+// also becomes invalid. THIS IS DIFFERENT THAN NORMAL SKIA which uses
+// reference counting for the pixel data. In normal Skia, you could assign
+// another bitmap to this device's bitmap and everything will work properly.
+// For us, that other bitmap will become invalid as soon as the device becomes
+// invalid, which may lead to subtle bugs. Therefore, DO NOT ASSIGN THE
+// DEVICE'S PIXEL DATA TO ANOTHER BITMAP, make sure you copy instead.
+class SK_API BitmapPlatformDevice : public SkBitmapDevice, public PlatformDevice {
+ public:
+  // Creates a BitmapPlatformDevice instance. |is_opaque| should be set if the
+  // caller knows the bitmap will be completely opaque and allows some
+  // optimizations.
+  // |context| may be NULL. If |context| is NULL, then the bitmap backing store
+  // is not initialized.
+  static BitmapPlatformDevice* Create(CGContextRef context,
+                                      int width, int height,
+                                      bool is_opaque, bool do_clear = false);
+
+  // Creates a context for |data| and calls Create.
+  // If |data| is NULL, then the bitmap backing store is not initialized.
+  static BitmapPlatformDevice* CreateWithData(uint8_t* data,
+                                              int width, int height,
+                                              bool is_opaque);
+
+  ~BitmapPlatformDevice() override;
+
+ protected:
+  BitmapPlatformDevice(CGContextRef context,
+                       const SkBitmap& bitmap);
+
+  SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;
+
+ private:
+  NativeDrawingContext BeginPlatformPaint(const SkMatrix& transform,
+                                          const SkIRect& clip_bounds) override;
+
+  void ReleaseBitmapContext();
+
+  // Loads the current transform and clip into the context. Can be called even
+  // when |bitmap_context_| is NULL (will be a NOP).
+  void LoadConfig(const SkMatrix& transform, const SkIRect& clip_bounds);
+
+  // Lazily-created graphics context used to draw into the bitmap.
+  CGContextRef bitmap_context_;
+
+  DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice);
+};
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_BITMAP_PLATFORM_DEVICE_MAC_H_