Add desired width & height to drawContext (as opposed to using the width & height of the RT)

src/gpu/GrDrawingManager.h

Index: src/gpu/GrDrawingManager.h
diff --git a/src/gpu/GrDrawingManager.h b/src/gpu/GrDrawingManager.h
index fa644b5286b0850f64151ac07e1c5fe146b8f129..c060d1c3e4746175acbbf73eec667c4947f74d04 100644
--- a/src/gpu/GrDrawingManager.h
+++ b/src/gpu/GrDrawingManager.h
@@ -31,7 +31,8 @@ public:
     bool wasAbandoned() const { return fAbandoned; }
     void freeGpuResources();
 
-    sk_sp<GrDrawContext> drawContext(sk_sp<GrRenderTarget> rt, const SkSurfaceProps*);
+    sk_sp<GrDrawContext> drawContext(int width, int height,
+                                     sk_sp<GrRenderTarget> rt, const SkSurfaceProps*);
 
     // The caller automatically gets a ref on the returned drawTarget. It must
     // be balanced by an unref call.