Revert of Revert of views: Move TOOLKIT_VIEWS definition in //ui/views/ from root.

build/config/BUILD.gn

 # Copyright (c) 2013 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/allocator.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/module_args/v8.gni")
@@ skipping 72 matching lines @@
   if (dont_embed_build_metadata) {
     defines += [ "DONT_EMBED_BUILD_METADATA" ]
   }
   if (dcheck_always_on) {
     defines += [ "DCHECK_ALWAYS_ON=1" ]
   }
   if (use_udev) {
     # TODO(brettw) should probably be "=1".
     defines += [ "USE_UDEV" ]
   }
-  if (toolkit_views) {
-    defines += [ "TOOLKIT_VIEWS=1" ]
-  }
   if (ui_compositor_image_transport) {
     # TODO(brettw) should probably be "=1".
     defines += [ "UI_COMPOSITOR_IMAGE_TRANSPORT" ]
   }
   if (use_ash) {
     defines += [ "USE_ASH=1" ]
   }
   if (use_aura) {
     defines += [ "USE_AURA=1" ]
   }
@@ skipping 283 matching lines @@
       "CoreFoundation.framework",
       "CoreGraphics.framework",
       "CoreText.framework",
       "Foundation.framework",
       "UIKit.framework",
     ]
   } else if (is_linux) {
     libs = [ "dl" ]
   }
 }