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

src/gpu/GrRenderTarget.cpp

Index: src/gpu/GrRenderTarget.cpp
diff --git a/src/gpu/GrRenderTarget.cpp b/src/gpu/GrRenderTarget.cpp
index 6a9d48997ee5b2c57f8ee0598d944feb8be8c41c..fa328a17f5a9af22b18a2369ac1ee22fedbd35fb 100644
--- a/src/gpu/GrRenderTarget.cpp
+++ b/src/gpu/GrRenderTarget.cpp
@@ -29,7 +29,8 @@ void GrRenderTarget::discard() {
         return;
     }
 
-    sk_sp<GrDrawContext> drawContext(context->drawContext(sk_ref_sp(this)));
+    sk_sp<GrDrawContext> drawContext(context->drawContext(this->width(), this->height(),
+                                                          sk_ref_sp(this)));
     if (!drawContext) {
         return;
     }