SkNonCopyable should be used with private inheritance.

This is mostly s/public SkNoncopyable/SkNoncopyable/g.

Two classes (SkDrawLooper::Context and SkPicture::OperationList) don't actually work with SkNoncopyable because they introduce a virtual destructor.  I added SkNoncopyableVirtual to make them work as intended.  Sort of questionable whether they really need to be noncopyable in the first place, but I guess it doesn't hurt to keep the behavior the same.

BUG=skia:
R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/226183018

git-svn-id: http://skia.googlecode.com/svn/trunk@14081 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrPlotMgr.h b/src/gpu/GrPlotMgr.h
index 6ea6086..8d55ed0 100644
--- a/src/gpu/GrPlotMgr.h
+++ b/src/gpu/GrPlotMgr.h
@@ -12,7 +12,7 @@
 #include "GrPoint.h"
 #include "SkTypes.h"
 
-class GrPlotMgr : public SkNoncopyable {
+class GrPlotMgr : SkNoncopyable {
 public:
     GrPlotMgr(int width, int height) {
         fDim.set(width, height);