<webview>: Move back, forward, canGoBack, canGoForward, go from content to chrome

chrome/browser/webview/webview_guest.h

Index: chrome/browser/webview/webview_guest.h
diff --git a/chrome/browser/webview/webview_guest.h b/chrome/browser/webview/webview_guest.h
index da406a0bf170b2f6b9b9dd40a96ed823ce47a1dd..e66274e1ca2f81a7c499d2c78dcd171636d5e7be 100644
--- a/chrome/browser/webview/webview_guest.h
+++ b/chrome/browser/webview/webview_guest.h
@@ -38,6 +38,10 @@ class WebViewGuest : public content::WebContentsObserver {
     return WebContentsObserver::web_contents();
   }
 
+  // If possible, navigate the guest to |relative_index| entries away from the
+  // current navigation entry.
+  void Go(int relative_index);
+
   int instance_id() const { return webview_instance_id_; }
 
   extensions::ScriptExecutor* script_executor() {