Enable FD export extension in swiftshader.

Previously Vulkan extensions VK_KHR_external_memory_fd and
VK_KHR_external_semaphore_fd were not enabled for swiftshader because
they were not supported. They are supported now, so they can be enabled.

Bug: 963988
Change-Id: I4d72fe965038615f19311e1e5bca5600b54035ab
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2353930
Auto-Submit: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797768}

gpu/vulkan/x/vulkan_implementation_x11.cc

@@ -146,15 +146,11 @@ bool VulkanImplementationX11::GetPhysicalDevicePresentationSupport(
 
 std::vector<const char*>
 VulkanImplementationX11::GetRequiredDeviceExtensions() {
-  std::vector<const char*> extensions;
-  // TODO(samans): Add these extensions once Swiftshader supports them.
-  // https://crbug.com/963988
-  if (!use_swiftshader()) {
-    extensions.push_back(VK_KHR_EXTERNAL_MEMORY_EXTENSION_NAME);
-    extensions.push_back(VK_KHR_EXTERNAL_MEMORY_FD_EXTENSION_NAME);
-    extensions.push_back(VK_KHR_EXTERNAL_SEMAPHORE_EXTENSION_NAME);
-    extensions.push_back(VK_KHR_EXTERNAL_SEMAPHORE_FD_EXTENSION_NAME);
-  }
+  std::vector<const char*> extensions = {
+      VK_KHR_EXTERNAL_MEMORY_EXTENSION_NAME,
+      VK_KHR_EXTERNAL_MEMORY_FD_EXTENSION_NAME,
+      VK_KHR_EXTERNAL_SEMAPHORE_EXTENSION_NAME,
+      VK_KHR_EXTERNAL_SEMAPHORE_FD_EXTENSION_NAME};
   if (using_surface_)
     extensions.push_back(VK_KHR_SWAPCHAIN_EXTENSION_NAME);
   return extensions;