Add skia::RefPtr class to wrap ref counted classes from Skia.

skia/ext/bitmap_platform_device_linux.cc

Index: skia/ext/bitmap_platform_device_linux.cc
diff --git a/skia/ext/bitmap_platform_device_linux.cc b/skia/ext/bitmap_platform_device_linux.cc
index 23a76830e4661409faaa3a18e84801e22ca68846..3a049e5a3864a7e7c5d40c652c64aeeb83c752ac 100644
--- a/skia/ext/bitmap_platform_device_linux.cc
+++ b/skia/ext/bitmap_platform_device_linux.cc
@@ -180,7 +180,8 @@ void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
 
 SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
                                uint8_t* data, OnFailureType failureType) {
-  SkDevice* dev = BitmapPlatformDevice::Create(width, height, is_opaque, data);
+  skia::RefPtr<SkDevice> dev = skia::AdoptRef(
+      BitmapPlatformDevice::Create(width, height, is_opaque, data));
   return CreateCanvas(dev, failureType);
 }