Enable vulkan (#11)

Author: xiaowei-guan

engine/src/build_overrides/vulkan_headers.gni

@@ -6,6 +6,6 @@
 # set anything.
 
 if (is_linux) {
-  vulkan_use_x11 = true
+  vulkan_use_x11 = false
   vulkan_use_wayland = true
 }

engine/src/flutter/impeller/tools/args.gni

@@ -17,7 +17,7 @@ declare_args() {
                               enable_unittests) && target_os != "fuchsia"
 
   # Whether the Vulkan backend is enabled.
-  impeller_enable_vulkan = (is_win || is_android || is_mac ||
+  impeller_enable_vulkan = (is_linux || is_win || is_android || is_mac ||
                             enable_unittests) && target_os != "fuchsia"
 }
 

engine/src/flutter/shell/config.gni

@@ -7,7 +7,7 @@ declare_args() {
 
   # The logic for enabling Vulkan and Metal is in tools/gn.
   shell_enable_metal = false
-  shell_enable_vulkan = false
+  shell_enable_vulkan = true
 
   shell_enable_software = true
 }

engine/src/flutter/tools/gn

@@ -599,7 +599,7 @@ def to_gn_args(args):
   # Enable Vulkan on all platforms except for iOS. This is just
   # to save on mobile binary size, as there's no reason the Vulkan embedder
   # features can't work on these platforms.
-  if gn_args['target_os'] not in ['ios', 'mac', 'linux']:
+  if gn_args['target_os'] not in ['ios', 'mac']:
     gn_args['skia_use_vulkan'] = True
     gn_args['skia_use_vma'] = False
     gn_args['shell_enable_vulkan'] = True