Split SkDevice out of SkBitmapDevice

https://codereview.chromium.org/22978012/



git-svn-id: http://skia.googlecode.com/svn/trunk@10830 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleCircle.cpp b/samplecode/SampleCircle.cpp
index f65ba01..87ca487 100644
--- a/samplecode/SampleCircle.cpp
+++ b/samplecode/SampleCircle.cpp
@@ -74,7 +74,7 @@
     }
 
     static void blowup(SkCanvas* canvas, const SkIRect& src, const SkRect& dst) {
-        SkDevice* device = canvas->getDevice();
+        SkBaseDevice* device = canvas->getDevice();
         const SkBitmap& bm = device->accessBitmap(false);
         canvas->drawBitmapRect(bm, &src, dst, NULL);
     }