Decompose //extensions/browser/BUILD.gn

extensions/browser/api/diagnostics/BUILD.gn

Index: extensions/browser/api/diagnostics/BUILD.gn
diff --git a/components/physical_web/data_source/BUILD.gn b/extensions/browser/api/diagnostics/BUILD.gn
similarity index 57%
copy from components/physical_web/data_source/BUILD.gn
copy to extensions/browser/api/diagnostics/BUILD.gn
index 70f92ff8c3092f5b95a86c9fe4ab91d776838d1a..cdef2936ccf301ed884f32bcdc92dc18ada189ce 100644
--- a/components/physical_web/data_source/BUILD.gn
+++ b/extensions/browser/api/diagnostics/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("data_source") {
+source_set("diagnostics") {
   sources = [
-    "physical_web_data_source.h",
-    "physical_web_listener.h",
+    "diagnostics_api.cc",
+    "diagnostics_api.h",
+    "diagnostics_api_chromeos.cc",
   ]
 
   deps = [
-    "//base",
+    "//extensions/common/api",
   ]
 }