ozone: drm: Remove OS_CHROMEOS #ifdefs around vulkan code

This uses some deprecated Intel mesa APIs but isn't actually Chrome OS
specific. Remove it to minimize Chrome OS #ifdefs.

Bug: 898234
Test: compile
Change-Id: I855e734646e0ff7b57150cf9d342156ea5a693aa
Reviewed-on: https://chromium-review.googlesource.com/c/1297239Reviewed-by: Daniel Nicoara <dnicoara@chromium.org>
Commit-Queue: Michael Spang <spang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602078}

ui/ozone/platform/drm/gpu/gbm_surface_factory.cc

@@ -29,7 +29,6 @@
 #if BUILDFLAG(ENABLE_VULKAN)
 #include "gpu/vulkan/vulkan_function_pointers.h"
 #include "ui/ozone/platform/drm/gpu/vulkan_implementation_gbm.h"
-#if defined(OS_CHROMEOS)
 #define VK_STRUCTURE_TYPE_DMA_BUF_IMAGE_CREATE_INFO_INTEL 1024
 typedef struct VkDmaBufImageCreateInfo_ {
   VkStructureType sType;
@@ -47,7 +46,6 @@ typedef VkResult(VKAPI_PTR* PFN_vkCreateDmaBufImageINTEL)(
     VkDeviceMemory* pMem,
     VkImage* pImage);
 #endif
-#endif
 
 namespace ui {
 
@@ -155,7 +153,6 @@ scoped_refptr<gfx::NativePixmap> GbmSurfaceFactory::CreateNativePixmapForVulkan(
     VkDevice vk_device,
     VkDeviceMemory* vk_device_memory,
     VkImage* vk_image) {
-#if defined(OS_CHROMEOS)
   std::unique_ptr<GbmBuffer> buffer;
   scoped_refptr<DrmFramebuffer> framebuffer;
 
@@ -209,9 +206,6 @@ scoped_refptr<gfx::NativePixmap> GbmSurfaceFactory::CreateNativePixmapForVulkan(
 
   return base::MakeRefCounted<GbmPixmap>(this, std::move(buffer),
                                          std::move(framebuffer));
-#else
-  return nullptr;
-#endif
 }
 #endif