Retract GrRenderTarget a bit

These sites don't necessarily need the full power of a GrRenderTarget object. This is a clean up for switching over to GrRenderTargetProxys.

Review URL: https://codereview.chromium.org/1486923004
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index e41a1b7..9b7fa31 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -137,7 +137,7 @@
     }
 
     SkIRect copyRect;
-    pipelineBuilder.clip().getConservativeBounds(rt, &copyRect);
+    pipelineBuilder.clip().getConservativeBounds(rt->width(), rt->height(), &copyRect);
 
     SkIRect drawIBounds;
     bounds.roundOut(&drawIBounds);