Split SkDevice into SkBaseDevice and SkBitmapDevice

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



git-svn-id: http://skia.googlecode.com/svn/trunk@10995 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/srcmode.cpp b/gm/srcmode.cpp
index 66729e2..e8a97e2 100644
--- a/gm/srcmode.cpp
+++ b/gm/srcmode.cpp
@@ -124,7 +124,7 @@
             SkImage::kPremul_AlphaType
         };
 #if SK_SUPPORT_GPU
-        SkDevice* dev = canvas->getDevice();
+        SkBaseDevice* dev = canvas->getDevice();
         if (!skipGPU && dev->accessRenderTarget()) {
             SkGpuDevice* gd = (SkGpuDevice*)dev;
             GrContext* ctx = gd->context();