Add support for a new GPU interface

src/gpu/GrContextFactory.cpp

Index: src/gpu/GrContextFactory.cpp
diff --git a/src/gpu/GrContextFactory.cpp b/src/gpu/GrContextFactory.cpp
index 6ed2c259e2ac95d3ea936648bdd9f4699310c7cf..1f371302f46a122db46799cfbcf141db1007eddd 100755
--- a/src/gpu/GrContextFactory.cpp
+++ b/src/gpu/GrContextFactory.cpp
@@ -76,7 +76,11 @@ GrContext* GrContextFactory::get(GLContextType type, GrGLStandard forcedGpuAPI)
 
     glCtx->makeCurrent();
     GrBackendContext p3dctx = reinterpret_cast<GrBackendContext>(glInterface.get());
+#ifdef SK_VULKAN
+    grCtx.reset(GrContext::Create(kVulkan_GrBackend, p3dctx, fGlobalOptions));
+#else
     grCtx.reset(GrContext::Create(kOpenGL_GrBackend, p3dctx, fGlobalOptions));
+#endif
     if (!grCtx.get()) {
         return NULL;
     }