Clean up test drawContext usage

include/core/SkDevice.h

Index: include/core/SkDevice.h
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 73c35c33419f0934797ae7994ab1732b4c35558a..e06650036dc10b35e8e3528f0153f6673c617bc2 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -106,8 +106,12 @@ public:
     /**
      * Return the device's associated gpu render target, or NULL.
      */
-    virtual GrRenderTarget* accessRenderTarget() { return NULL; }
+    virtual GrRenderTarget* accessRenderTarget() { return nullptr; }

[bsalomon, 2016/04/28 15:03:34]

Is this still needed?

[robertphillips, 2016/04/28 18:49:57]

Unfortunately, draw_filter_into_device still calls the virtual version. Once
that is cleaned up the virtual can go away.

I've added a TODO.

 
+    /**
+     * Don't call this!

[bsalomon, 2016/04/28 15:03:34]

When is it OK to call this? Should we say for testing? If device is internal is
this such a bad method to have?

[robertphillips, 2016/04/28 18:49:57]

It is testing-only except for MultiPictureDraw (where it is used to get the
numSamples needed for the hoisted layers) and VisualBench (where it is used for
a faster blit). 

The comment is more a prayer that it not become the new accessRenderTarget.

+     */
+    virtual GrDrawContext* accessDrawContext() { return nullptr; }
 
     /**
      *  Return the device's origin: its offset in device coordinates from