Reland "Always include public/include headers for vulkan and just guard src files with SK_VULKAN."

This reverts commit 684b506f3589ecc78eebe8d92082be31a5fbe348.

Reason for revert: Chrome change has landed to fix broken chrome roll.

Original change's description:
> Revert "Always include public/include headers for vulkan and just guard src files with SK_VULKAN."
>
> This reverts commit 6e2d607334cc57c22e3a52179743763828ea84b2.
>
> Reason for revert: chrome roll
>
> Original change's description:
> > Always include public/include headers for vulkan and just guard src files with SK_VULKAN.
> >
> > This should allow a client to build a skia library that doesn't use vulkan but still
> > has all the public headers defined so that they don't have to build two versions of
> > their code.
> >
> > Bug: chromium:862144
> > Change-Id: I0eecbe0bc48123619f217e2cf318eb9a8c77ccb2
> > Reviewed-on: https://skia-review.googlesource.com/158661
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> > Commit-Queue: Greg Daniel <egdaniel@google.com>
>
> TBR=egdaniel@google.com,bsalomon@google.com,cblume@chromium.org
>
> Change-Id: I76ae6f435333755fa5d546fc1e5999a324b4fd05
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: chromium:862144
> Reviewed-on: https://skia-review.googlesource.com/c/159000
> Reviewed-by: Mike Klein <mtklein@google.com>
> Commit-Queue: Mike Klein <mtklein@google.com>

TBR=egdaniel@google.com,mtklein@google.com,bsalomon@google.com,cblume@chromium.org

Change-Id: Id019b428f880efbd7ead8dee4178c6190469a290
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:862144
Reviewed-on: https://skia-review.googlesource.com/c/159145
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/GrDirectContext.cpp b/src/gpu/GrDirectContext.cpp
index 14133cd..59b984c 100644
--- a/src/gpu/GrDirectContext.cpp
+++ b/src/gpu/GrDirectContext.cpp
@@ -147,14 +147,19 @@
     return context;
 }
 
-#ifdef SK_VULKAN
 sk_sp<GrContext> GrContext::MakeVulkan(const GrVkBackendContext& backendContext) {
+#ifdef SK_VULKAN
     GrContextOptions defaultOptions;
     return MakeVulkan(backendContext, defaultOptions);
+#else
+    return nullptr;
+#endif
 }
 
 sk_sp<GrContext> GrContext::MakeVulkan(const GrVkBackendContext& backendContext,
                                        const GrContextOptions& options) {
+#ifdef SK_VULKAN
+    GrContextOptions defaultOptions;
     sk_sp<GrContext> context(new GrDirectContext(kVulkan_GrBackend));
 
     context->fGpu = GrVkGpu::Make(backendContext, options, context.get());
@@ -167,8 +172,10 @@
         return nullptr;
     }
     return context;
-}
+#else
+    return nullptr;
 #endif
+}
 
 #ifdef SK_METAL
 sk_sp<GrContext> GrContext::MakeMetal(void* device, void* queue) {