Require WebLocalFrame to be created with a non-null client

third_party/WebKit/public/web/WebLocalFrame.h

Index: third_party/WebKit/public/web/WebLocalFrame.h
diff --git a/third_party/WebKit/public/web/WebLocalFrame.h b/third_party/WebKit/public/web/WebLocalFrame.h
index dc4815df7ac7cc9a4db735fe1dfab17958392b25..39814cc78b782b3453dc88cff46f047ca273f28f 100644
--- a/third_party/WebKit/public/web/WebLocalFrame.h
+++ b/third_party/WebKit/public/web/WebLocalFrame.h
@@ -37,7 +37,7 @@ struct WebPrintPresetOptions;
 class WebLocalFrame : public WebFrame {
 public:
     // Creates a WebFrame. Delete this WebFrame by calling WebFrame::close().
-    // It is valid to pass a null client pointer.
+    // WebFrameClient may not be null.

[esprehn, 2016/09/29 04:28:42]

we should probably pass a reference then

[dcheng, 2016/09/29 04:42:38]

I'm not opposed to changing this, but it's inconsistent with how all the
public/web interfaces are currently defined. If we want to change this, it might
be better to do a separate CL.

     BLINK_EXPORT static WebLocalFrame* create(WebTreeScopeType, WebFrameClient*, WebFrame* opener = nullptr);
 
     // Used to create a provisional local frame in prepration for replacing a