Moved window opening callback to WebStateDelegate.

ios/web/web_state/web_state_impl.h

Index: ios/web/web_state/web_state_impl.h
diff --git a/ios/web/web_state/web_state_impl.h b/ios/web/web_state/web_state_impl.h
index 21234069cb2fcd2a024d1c149437fc722a6530e0..7a160ed40ba1922acdfb3ae4048c6ec62dcac93a 100644
--- a/ios/web/web_state/web_state_impl.h
+++ b/ios/web/web_state/web_state_impl.h
@@ -253,6 +253,14 @@ class WebStateImpl : public WebState, public NavigationManagerDelegate {
                            NSString* default_prompt_text,
                            const DialogClosedCallback& callback);
 
+  // Instructs the delegate to create a new web state. Called when this WebState
+  // wants to open a new window. |url| is the URL of the new window;
+  // |opener_url| is the URL of the page which requested a window to be open;
+  // |initiated_by_user| is true if action was caused by the user.
+  WebState* CreateNewWebState(const GURL& url,
+                              const GURL& opener_url,
+                              bool initiated_by_user);
+
   // Notifies the delegate that request receives an authentication challenge
   // and is unable to respond using cached credentials.
   void OnAuthRequired(NSURLProtectionSpace* protection_space,