Remove usage of no-op macro DEFINE_WEB_STATE_USER_DATA_KEY.

This CL removes macro usage from /ios/chrome.

This CL was uploaded by git cl split.

R=rohitrao@chromium.org

Bug: 589840
Change-Id: Ibcc14267aaa966b1833dd1537989a7bc5ae9a010
Reviewed-on: https://chromium-review.googlesource.com/c/1351952Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Mike Dougherty <michaeldo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612314}

ios/chrome/browser/app_launcher/app_launcher_tab_helper.mm

@@ -28,8 +28,6 @@
 #error "This file requires ARC support."
 #endif
 
-DEFINE_WEB_STATE_USER_DATA_KEY(AppLauncherTabHelper);
-
 namespace {
 
 bool IsValidAppUrl(const GURL& app_url) {

ios/chrome/browser/search_engines/search_engine_tab_helper.mm

@@ -22,8 +22,6 @@
 #error "This file requires ARC support."
 #endif
 
-DEFINE_WEB_STATE_USER_DATA_KEY(SearchEngineTabHelper);
-
 namespace {
 
 const char kCommandPrefix[] = "searchEngine";