[ios] Rename RootCoordinator to ChromeRootCoordinator.

BUG=

Review-Url: https://codereview.chromium.org/2810163002
Cr-Commit-Position: refs/heads/master@{#464048}
diff --git a/ios/chrome/browser/BUILD.gn b/ios/chrome/browser/BUILD.gn
index c0be92b..de6beb48 100644
--- a/ios/chrome/browser/BUILD.gn
+++ b/ios/chrome/browser/BUILD.gn
@@ -28,6 +28,8 @@
     "chrome_paths.h",
     "chrome_paths.mm",
     "chrome_paths_internal.h",
+    "chrome_root_coordinator.h",
+    "chrome_root_coordinator.mm",
     "chrome_switches.cc",
     "chrome_switches.h",
     "chrome_url_constants.cc",
@@ -57,8 +59,6 @@
     "pref_names.cc",
     "pref_names.h",
     "procedural_block_types.h",
-    "root_coordinator.h",
-    "root_coordinator.mm",
     "tab_parenting_global_observer.cc",
     "tab_parenting_global_observer.h",
     "web_data_service_factory.cc",