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

This reverts commit a55e214bbe3942a098d97906a0f008d59dd1fafb.

Reason for revert:google3 should be fixed now

Original change's description:
> Revert "Reland "Always include public/include headers for vulkan and just guard src files with SK_VULKAN.""
> 
> This reverts commit 55aea84baa53f2d7e7e876b09fd590f046ff9ab9.
> 
> Reason for revert: Google3 roll failing like
> 
> third_party/skia/HEAD/include/gpu/vk/GrVkDefines.h:15:10: fatal error: '../../../third_party/vulkan/SkiaVulkan.h' file not found
> #include "../../../third_party/vulkan/SkiaVulkan.h"
> 
> 
> Original change's description:
> > 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>
> 
> TBR=egdaniel@google.com,mtklein@google.com,bsalomon@google.com,cblume@chromium.org
> 
> Change-Id: I0e5c72e2d79dac28021b02168a9e11ac08db765c
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: chromium:862144
> Reviewed-on: https://skia-review.googlesource.com/c/159155
> 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: I58f7f8ca5281cd5fe0c145c01e9b9465c9b9ec31
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:862144
Reviewed-on: https://skia-review.googlesource.com/159260
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 3e8b240..886c275 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1362,8 +1362,8 @@
       deps += [ "//third_party/angle2" ]
       sources += [ "tools/gpu/gl/angle/GLTestContext_angle.cpp" ]
     }
+    public_include_dirs += [ "third_party/vulkan" ]
     if (skia_use_vulkan) {
-      public_include_dirs += [ "third_party/vulkan" ]
       sources += [ "tools/gpu/vk/VkTestContext.cpp" ]
       sources += [ "tools/gpu/vk/VkTestUtils.cpp" ]
       if (defined(skia_moltenvk_path) && skia_moltenvk_path != "") {