Limit manual control of platform painting

skia/ext/bitmap_platform_device_skia.h

Index: skia/ext/bitmap_platform_device_skia.h
diff --git a/skia/ext/bitmap_platform_device_skia.h b/skia/ext/bitmap_platform_device_skia.h
index 4a0d67a976990cfa7827cf60a214d019f7d64ff4..893c133f656865d1846c07470430db20fa4ddbb3 100644
--- a/skia/ext/bitmap_platform_device_skia.h
+++ b/skia/ext/bitmap_platform_device_skia.h
@@ -10,6 +10,7 @@
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "skia/ext/platform_canvas.h"
 #include "skia/ext/platform_device.h"
 
 namespace skia {
@@ -40,13 +41,15 @@ class BitmapPlatformDevice : public SkBitmapDevice, public PlatformDevice {
   explicit BitmapPlatformDevice(const SkBitmap& other);
   ~BitmapPlatformDevice() override;
 
+ protected:
   PlatformSurface BeginPlatformPaint() override;
 
- protected:
   SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice);
+
+  friend class skia::ScopedPlatformPaint;
 };
 
 }  // namespace skia