Make SkDevice::onReadPixels take a const& rather than const*



git-svn-id: http://skia.googlecode.com/svn/trunk@2587 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index 047fd07..d394d12 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -141,7 +141,7 @@
     friend class SkAutoTexCache;
     
     // overrides from SkDevice
-    virtual bool onReadPixels(const SkBitmap* bitmap,
+    virtual bool onReadPixels(const SkBitmap& bitmap,
                               int x, int y) SK_OVERRIDE;