Moved window opening callback to WebStateDelegate.

ios/web/public/test/crw_mock_web_state_delegate.mm

Index: ios/web/public/test/crw_mock_web_state_delegate.mm
diff --git a/ios/web/public/test/crw_mock_web_state_delegate.mm b/ios/web/public/test/crw_mock_web_state_delegate.mm
index f6dfa0a51b329e9dc8ba7f925b6ec99f69335645..06cbb759f00186988fcd01241fa84f4e0c181f86 100644
--- a/ios/web/public/test/crw_mock_web_state_delegate.mm
+++ b/ios/web/public/test/crw_mock_web_state_delegate.mm
@@ -17,10 +17,20 @@
 }
 
 @synthesize webState = _webState;
+@synthesize webStateCreationRequested = _webStateCreationRequested;
 @synthesize repostFormWarningRequested = _repostFormWarningRequested;
 @synthesize authenticationRequested = _authenticationRequested;
 
 - (web::WebState*)webState:(web::WebState*)webState
+    createNewWebStateForURL:(const GURL&)URL
+                  openerURL:(const GURL&)openerURL
+            initiatedByUser:(BOOL)initiatedByUser {
+  _webState = webState;
+  _webStateCreationRequested = YES;
+  return nil;
+}
+
+- (web::WebState*)webState:(web::WebState*)webState
          openURLWithParams:(const web::WebState::OpenURLParams&)params {
   _webState = webState;
   _openURLParams.reset(new web::WebState::OpenURLParams(params));