Make skia::GetNativeDrawingContext Windows-only

skia/ext/bitmap_platform_device_win.cc

 // 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.
 
 #include <windows.h>
 #include <psapi.h>
 #include <stddef.h>
 
 #include "base/debug/gdi_debug_util_win.h"
 #include "base/logging.h"
@@ skipping 30 matching lines @@
     temp_rect.right = canvas->imageInfo().width();
     temp_rect.top = 0;
     temp_rect.bottom = canvas->imageInfo().height();
     src_rect = &temp_rect;
   }
   skia::CopyHDC(skia::GetNativeDrawingContext(canvas), destination_hdc, x, y,
                 canvas->imageInfo().isOpaque(), *src_rect,
                 canvas->getTotalMatrix());
 }
 
+HDC GetNativeDrawingContext(SkCanvas* canvas) {
+  PlatformDevice* platform_device = GetPlatformDevice(canvas->getTopDevice(true));
+  if (!platform_device)
+    return nullptr;
+
+  // Compensate for drawing to a layer rather than the entire canvas
+  SkMatrix ctm;
+  SkIRect clip_bounds;
+  canvas->temporary_internal_describeTopLayer(&ctm, &clip_bounds);
+
+  return platform_device->BeginPlatformPaint(ctm, clip_bounds);
+}
+
 HDC BitmapPlatformDevice::GetBitmapDC(const SkMatrix& transform,
                                       const SkIRect& clip_bounds) {
   if (!hdc_) {
     hdc_ = CreateCompatibleDC(NULL);
     InitializeDC(hdc_);
     old_hbitmap_ = static_cast<HBITMAP>(SelectObject(hdc_, hbitmap_));
   }
 
   LoadConfig(transform, clip_bounds);
   return hdc_;
@@ skipping 150 matching lines @@
     int height,
     bool is_opaque,
     HANDLE shared_section,
     OnFailureType failureType) {
   sk_sp<SkBaseDevice> dev(
       BitmapPlatformDevice::Create(width, height, is_opaque, shared_section));
   return CreateCanvas(dev, failureType);
 }
 
 }  // namespace skia