Change call-sites now that SkCanvas is not ref-counted

skia/ext/bitmap_platform_device_mac.cc

Index: skia/ext/bitmap_platform_device_mac.cc
diff --git a/skia/ext/bitmap_platform_device_mac.cc b/skia/ext/bitmap_platform_device_mac.cc
index 06a41390b5db0dc44810b7a373df9537238a49bf..bf02a89a5e1bc31b930023fba91183325c104c35 100644
--- a/skia/ext/bitmap_platform_device_mac.cc
+++ b/skia/ext/bitmap_platform_device_mac.cc
@@ -260,16 +260,22 @@ SkBaseDevice* BitmapPlatformDevice::onCreateDevice(const CreateInfo& cinfo,
 
 // PlatformCanvas impl
 
-SkCanvas* CreatePlatformCanvas(CGContextRef ctx, int width, int height,
-                               bool is_opaque, OnFailureType failureType) {
+std::unique_ptr<SkCanvas> CreatePlatformCanvas(CGContextRef ctx,
+                                               int width,
+                                               int height,
+                                               bool is_opaque,
+                                               OnFailureType failureType) {
   const bool do_clear = false;
   sk_sp<SkBaseDevice> dev(
       BitmapPlatformDevice::Create(ctx, width, height, is_opaque, do_clear));
   return CreateCanvas(dev, failureType);
 }
 
-SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
-                               uint8_t* data, OnFailureType failureType) {
+std::unique_ptr<SkCanvas> CreatePlatformCanvas(int width,
+                                               int height,
+                                               bool is_opaque,
+                                               uint8_t* data,
+                                               OnFailureType failureType) {
   sk_sp<SkBaseDevice> dev(
       BitmapPlatformDevice::CreateWithData(data, width, height, is_opaque));
   return CreateCanvas(dev, failureType);