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

ios/chrome/browser/bookmarks/BUILD.gn

Index: ios/chrome/browser/bookmarks/BUILD.gn
diff --git a/ios/chrome/browser/bookmarks/BUILD.gn b/ios/chrome/browser/bookmarks/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..8bd1d51bf6950d0d6fa76ad0b5103dd1c990d13e
--- /dev/null
+++ b/ios/chrome/browser/bookmarks/BUILD.gn
@@ -0,0 +1,52 @@
+# Copyright 2016 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.
+
+source_set("bookmarks") {
+  sources = [
+    "bookmark_client_impl.cc",
+    "bookmark_client_impl.h",
+    "bookmark_model_factory.cc",
+    "bookmark_model_factory.h",
+    "startup_task_runner_service_factory.cc",
+    "startup_task_runner_service_factory.h",
+  ]
+  deps = [
+    "//base",
+    "//components/bookmarks/browser",
+    "//components/favicon/core",
+    "//components/favicon_base",
+    "//components/history/core/browser",
+    "//components/keyed_service/core",
+    "//components/keyed_service/ios",
+    "//components/prefs",
+    "//components/undo",
+    "//ios/chrome/browser:browser_no_public_deps",
+    "//ios/chrome/browser/browser_state",
+    "//ios/chrome/browser/favicon",
+    "//ios/chrome/browser/history",
+    "//ios/chrome/browser/undo",
+    "//ios/web",
+  ]
+  public_deps = [
+    ":bookmarks_utils",
+  ]
+  allow_circular_includes_from = [
+    "//ios/chrome/browser/history",
+    ":bookmarks_utils",
+  ]
+}
+
+source_set("bookmarks_utils") {
+  sources = [
+    "bookmarks_utils.cc",
+    "bookmarks_utils.h",
+  ]
+  deps = [
+    "//base",
+    "//components/bookmarks/browser",
+    "//components/prefs",
+    "//ios/chrome/browser:browser_no_public_deps",
+    "//ios/chrome/browser/browser_state",
+  ]
+}