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/GrSoftwarePathRenderer.cpp b/src/gpu/GrSoftwarePathRenderer.cpp
index de833a6..a136886 100644
--- a/src/gpu/GrSoftwarePathRenderer.cpp
+++ b/src/gpu/GrSoftwarePathRenderer.cpp
@@ -39,7 +39,7 @@
         return false;
     }
 
-    pipelineBuilder->clip().getConservativeBounds(rt, devClipBounds);
+    pipelineBuilder->clip().getConservativeBounds(rt->width(), rt->height(), devClipBounds);
 
     if (devClipBounds->isEmpty()) {
         *devPathBounds = SkIRect::MakeWH(rt->width(), rt->height());