Add glBlendBarrierKHR to Skia's GL bindings.

gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc

Index: gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc
diff --git a/gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc b/gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc
index c8cc36cdb70ccc0ee246a07781f7de7b9a63f9b2..36ff45bc7a3bcb563399537c819964fdd1907f4a 100644
--- a/gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc
+++ b/gpu/skia_bindings/gl_bindings_skia_cmd_buffer.cc
@@ -29,6 +29,7 @@ GrGLInterface* CreateCommandBufferSkiaGLBinding() {
   functions->fBindBuffer = glBindBuffer;
   functions->fBindTexture = glBindTexture;
   functions->fBindVertexArray = glBindVertexArrayOES;
+  functions->fBlendBarrier = glBlendBarrierKHR;
   functions->fBlendColor = glBlendColor;
   functions->fBlendEquation = glBlendEquation;
   functions->fBlendFunc = glBlendFunc;