Decompose //extensions/browser/BUILD.gn

extensions/browser/api/virtual_keyboard_private/BUILD.gn

Index: extensions/browser/api/virtual_keyboard_private/BUILD.gn
diff --git a/components/physical_web/webui/BUILD.gn b/extensions/browser/api/virtual_keyboard_private/BUILD.gn
similarity index 51%
copy from components/physical_web/webui/BUILD.gn
copy to extensions/browser/api/virtual_keyboard_private/BUILD.gn
index f3d6432dd2b700c0f266293e7ce3eef7ca158809..75d1e5a30983d872baa3eee5c465061ac2d6694a 100644
--- a/components/physical_web/webui/BUILD.gn
+++ b/extensions/browser/api/virtual_keyboard_private/BUILD.gn
@@ -2,13 +2,14 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("webui") {
+source_set("virtual_keyboard_private") {
   sources = [
-    "physical_web_ui_constants.cc",
-    "physical_web_ui_constants.h",
+    "virtual_keyboard_delegate.h",
+    "virtual_keyboard_private_api.cc",
+    "virtual_keyboard_private_api.h",
   ]
 
   deps = [
-    "//base",
+    "//extensions/common/api",
   ]
 }