[DevTools] Added public method for async execution of scripts

public/web/WebScriptSource.h

Index: public/web/WebScriptSource.h
diff --git a/public/web/WebScriptSource.h b/public/web/WebScriptSource.h
index 8d2709679e2b949c2b75fd3cb652233e9729e7e9..0738adc425b68c3837126133fc108b8d5a95d6e4 100644
--- a/public/web/WebScriptSource.h
+++ b/public/web/WebScriptSource.h
@@ -36,6 +36,8 @@
 
 namespace blink {
 
+class ScriptSourceCode;
+
 struct WebScriptSource {
     WebString code;
     WebURL url;
@@ -47,6 +49,10 @@ struct WebScriptSource {
         : code(code), url(url), startLine(1) { }
     WebScriptSource(const WebString& code, const WebURL& url, int startLine)
         : code(code), url(url), startLine(startLine) { }
+
+#if BLINK_IMPLEMENTATION
+    operator ScriptSourceCode() const;
+#endif
 };
 
 } // namespace blink