Remove chrome_earl_grey helper waitForErrorPage; it has no callsites.

Bug: 922813
Change-Id: I9017954c687da3323127dd93b9afe63bfa9ee57b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1643497
Commit-Queue: ericale <ericale@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666088}

ios/chrome/test/earl_grey/chrome_earl_grey.h

@@ -387,11 +387,6 @@ id ExecuteJavaScript(NSString* javascript, NSError* __autoreleasing* out_error);
 // CHROME_EG_ASSERT_NO_ERROR is removed.
 - (NSError*)waitForStaticHTMLViewNotContainingText:(NSString*)text;
 
-// Waits for a Chrome error page.
-// If the condition is not met within a timeout returns an NSError indicating
-// why the operation failed, otherwise nil.
-- (NSError*)waitForErrorPage WARN_UNUSED_RESULT;
-
 #pragma mark - Sync Utilities
 
 // Injects a bookmark into the fake sync server with |URL| and |title|.

ios/chrome/test/earl_grey/chrome_earl_grey.mm

@@ -19,7 +19,6 @@
 #if defined(CHROME_EARL_GREY_1)
 #import <WebKit/WebKit.h>
 
-#include "components/strings/grit/components_strings.h"  // nogncheck
 #import "ios/chrome/browser/ui/static_content/static_html_view_controller.h"  // nogncheck
 #import "ios/chrome/test/app/chrome_test_util.h"                   // nogncheck
 #import "ios/chrome/test/app/history_test_util.h"                  // nogncheck
@@ -32,7 +31,6 @@
 #import "ios/web/public/test/web_view_content_test_util.h"         // nogncheck
 #import "ios/web/public/test/web_view_interaction_test_util.h"     // nogncheck
 #import "ios/web/public/web_state/web_state.h"                     // nogncheck
-#include "ui/base/l10n/l10n_util.h"                                // nogncheck
 #endif
 
 using base::test::ios::kWaitForJSCompletionTimeout;
@@ -602,12 +600,6 @@ id ExecuteJavaScript(NSString* javascript,
 
 #pragma mark - Navigation Utilities
 
-- (NSError*)waitForErrorPage {
-  NSString* const kErrorPageText =
-      l10n_util::GetNSString(IDS_ERRORPAGES_HEADING_NOT_AVAILABLE);
-  return [self waitForStaticHTMLViewContainingText:kErrorPageText];
-}
-
 - (NSError*)waitForStaticHTMLViewContainingText:(NSString*)text {
   bool hasStaticView = WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, ^{
     return chrome_test_util::StaticHtmlViewContainingText(