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

skia/ext/bitmap_platform_device_skia.cc

Index: skia/ext/bitmap_platform_device_skia.cc
diff --git a/skia/ext/bitmap_platform_device_skia.cc b/skia/ext/bitmap_platform_device_skia.cc
index 77957af919be5e3f18b35026464fa0e3b91b54fe..d19810badac5da003d369779c1e097b818fe3442 100644
--- a/skia/ext/bitmap_platform_device_skia.cc
+++ b/skia/ext/bitmap_platform_device_skia.cc
@@ -60,8 +60,11 @@ NativeDrawingContext BitmapPlatformDevice::BeginPlatformPaint(
 
 // PlatformCanvas impl
 
-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::Create(width, height, is_opaque, data));
   return CreateCanvas(dev, failureType);