Add NULL GL context implementation. Use in bench (-nullgl) and SampleApp (backspace key)

Review URL: http://codereview.appspot.com/5303080/


git-svn-id: http://skia.googlecode.com/svn/trunk@2545 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/SkNullGLContext.cpp b/src/gpu/SkNullGLContext.cpp
new file mode 100644
index 0000000..04e63d8
--- /dev/null
+++ b/src/gpu/SkNullGLContext.cpp
@@ -0,0 +1,13 @@
+
+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkNullGLContext.h"
+
+const GrGLInterface* SkNullGLContext::createGLContext() {
+    return GrGLCreateNullInterface();
+};