Enable SwiftShader fallback on desktop Linux.

content/browser/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//gpu/vulkan/features.gni")
 import("//media/media_options.gni")
 import("//ppapi/features/features.gni")
 import("//printing/features/features.gni")
@@ skipping 1745 matching lines @@
 
   if (is_linux && use_aura) {
     deps += [ "//build/linux:fontconfig" ]
   }
 
   if (use_x11) {
     configs += [ "//build/config/linux:x11" ]
     deps += [ "//ui/gfx/x" ]
   }
 
+  if (is_linux && !is_chromeos && use_x11 &&
+      (target_cpu == "x86" || target_cpu == "x64")) {
+    deps += [ "//third_party/swiftshader" ]
+  }
+
   if (use_pango) {
     configs += [ "//build/config/linux/pangocairo" ]
   }
 
   if (is_android) {
     sources += [
       "accessibility/accessibility_tree_formatter_android.cc",
       "accessibility/browser_accessibility_android.cc",
       "accessibility/browser_accessibility_android.h",
       "accessibility/browser_accessibility_manager_android.cc",
@@ skipping 278 matching lines @@
   if (!is_component_build) {
     public_deps = [
       ":browser",
     ]
   } else {
     public_deps = [
       "//third_party/leveldatabase",
     ]
   }
 }