Split //ios/chrome/browser in multiple targets.

ios/chrome/browser/browser_state_metrics/BUILD.gn

Index: ios/chrome/browser/browser_state_metrics/BUILD.gn
diff --git a/extensions/browser/api/app_runtime/BUILD.gn b/ios/chrome/browser/browser_state_metrics/BUILD.gn
similarity index 59%
copy from extensions/browser/api/app_runtime/BUILD.gn
copy to ios/chrome/browser/browser_state_metrics/BUILD.gn
index 9951138b8a22d2aa4a5d0c22092c3d89197f775b..1993bb754c5cf0cb7394c2294d3d11908572f003 100644
--- a/extensions/browser/api/app_runtime/BUILD.gn
+++ b/ios/chrome/browser/browser_state_metrics/BUILD.gn
@@ -2,13 +2,12 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("app_runtime") {
+source_set("browser_state_metrics") {
   sources = [
-    "app_runtime_api.cc",
-    "app_runtime_api.h",
+    "browser_state_metrics.cc",
+    "browser_state_metrics.h",
   ]
-
   deps = [
-    "//extensions/common/api",
+    "//components/profile_metrics",
   ]
 }