Remove GrRefCnt.h in favor of SkRefCnt.h

This removes GrRefCnt.h with all its tyepdefs and #defines and just switch them
to the Sk* equivalents.

GrSafeSetNull was promoted to SkSafeSetNull in SkRefCnt.h.

BUG=None
TEST=none, no functional changes.
R=bsalomon@google.com, robertphillips@google.com

Author: tfarina@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23904003

git-svn-id: http://skia.googlecode.com/svn/trunk@11151 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/texdata.cpp b/gm/texdata.cpp
index 0e2d7fd..b2c7139 100644
--- a/gm/texdata.cpp
+++ b/gm/texdata.cpp
@@ -93,7 +93,7 @@
                 if (!texture) {
                     return;
                 }
-                GrAutoUnref au(texture);
+                SkAutoUnref au(texture);
 
                 GrContext::AutoClip acs(ctx, SkRect::MakeWH(2*S, 2*S));