[multiball] Cleanup some includes/gn deps in main controller.

Removes the surprisingly few unused includes and GN deps I could find.

Fixed: 1045664
Change-Id: I2cab2467857b1d60b527911cc54074af8f8e5677
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2424253
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810752}

ios/chrome/app/BUILD.gn

@@ -235,7 +235,6 @@ source_set("app_internal") {
     "//ios/chrome/browser/ui/first_run",
     "//ios/chrome/browser/ui/main",
     "//ios/chrome/browser/ui/main:scene",
-    "//ios/chrome/browser/ui/scoped_ui_blocker",
     "//ios/chrome/browser/ui/tab_grid",
     "//ios/chrome/browser/ui/tab_grid:tab_grid_ui",
     "//ios/chrome/browser/ui/table_view",

ios/chrome/app/main_controller.mm

@@ -90,12 +90,10 @@
 #import "ios/chrome/browser/ui/first_run/welcome_to_chrome_view_controller.h"
 #import "ios/chrome/browser/ui/main/browser_view_wrangler.h"
 #import "ios/chrome/browser/ui/main/scene_delegate.h"
-#import "ios/chrome/browser/ui/scoped_ui_blocker/scoped_ui_blocker.h"
 #import "ios/chrome/browser/ui/ui_feature_flags.h"
 #include "ios/chrome/browser/ui/util/multi_window_support.h"
 #import "ios/chrome/browser/ui/webui/chrome_web_ui_ios_controller_factory.h"
 #import "ios/chrome/browser/url_loading/url_loading_params.h"
-#import "ios/chrome/browser/web/tab_id_tab_helper.h"
 #import "ios/chrome/browser/web_state_list/web_state_list.h"
 #include "ios/chrome/common/app_group/app_group_constants.h"
 #include "ios/chrome/common/app_group/app_group_utils.h"