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/src/gpu/SkGrPixelRef.cpp b/src/gpu/SkGrPixelRef.cpp
index 98819bf..dc5d755 100644
--- a/src/gpu/SkGrPixelRef.cpp
+++ b/src/gpu/SkGrPixelRef.cpp
@@ -94,7 +94,7 @@
 #endif
 
     SkGrPixelRef* pixelRef = SkNEW_ARGS(SkGrPixelRef, (dst));
-    GrSafeUnref(dst);
+    SkSafeUnref(dst);
     return pixelRef;
 }
 
@@ -114,7 +114,7 @@
         fSurface = surface;
     }
     fUnlock = transferCacheLock;
-    GrSafeRef(surface);
+    SkSafeRef(surface);
 }
 
 SkGrPixelRef::~SkGrPixelRef() {
@@ -125,7 +125,7 @@
             context->unlockScratchTexture(texture);
         }
     }
-    GrSafeUnref(fSurface);
+    SkSafeUnref(fSurface);
 }
 
 GrTexture* SkGrPixelRef::getTexture() {