Move ExecuteScript method from WebFrame to WebLocalFrame.

components/plugins/renderer/webview_plugin.cc

Index: components/plugins/renderer/webview_plugin.cc
diff --git a/components/plugins/renderer/webview_plugin.cc b/components/plugins/renderer/webview_plugin.cc
index 80404cfe8a37bf45a2894bf8631a452680cf3fef..b5da7d5f7011650d25c85bf8d6d818df512926f8 100644
--- a/components/plugins/renderer/webview_plugin.cc
+++ b/components/plugins/renderer/webview_plugin.cc
@@ -68,7 +68,7 @@ WebViewPlugin* WebViewPlugin::Create(content::RenderView* render_view,
                                      const GURL& url) {
   DCHECK(url.is_valid()) << "Blink requires the WebView to have a valid URL.";
   WebViewPlugin* plugin = new WebViewPlugin(render_view, delegate, preferences);
-  plugin->web_view()->MainFrame()->LoadHTMLString(html_data, url);
+  plugin->main_frame()->LoadHTMLString(html_data, url);
   return plugin;
 }
 
@@ -271,6 +271,13 @@ WebViewPlugin::WebViewHelper::~WebViewHelper() {
   web_view_->Close();
 }
 
+blink::WebLocalFrame* WebViewPlugin::WebViewHelper::main_frame() {
+  // WebViewHelper doesn't support OOPIFs so the main frame will
+  // always be local.
+  DCHECK(web_view_->MainFrame()->IsWebLocalFrame());
+  return static_cast<WebLocalFrame*>(web_view_->MainFrame());
+}
+
 bool WebViewPlugin::WebViewHelper::AcceptsLoadDrops() {
   return false;
 }
@@ -296,11 +303,7 @@ void WebViewPlugin::WebViewHelper::StartDragging(blink::WebReferrerPolicy,
                                                  const WebImage&,
                                                  const WebPoint&) {
   // Immediately stop dragging.
-  DCHECK(web_view_->MainFrame()->IsWebLocalFrame());
-  web_view_->MainFrame()
-      ->ToWebLocalFrame()
-      ->FrameWidget()
-      ->DragSourceSystemDragEnded();
+  main_frame()->FrameWidget()->DragSourceSystemDragEnded();
 }
 
 bool WebViewPlugin::WebViewHelper::AllowsBrokenNullLayerTreeView() const {
@@ -345,8 +348,7 @@ void WebViewPlugin::WebViewHelper::DidClearWindowObject() {
 
   v8::Isolate* isolate = blink::MainThreadIsolate();
   v8::HandleScope handle_scope(isolate);
-  v8::Local<v8::Context> context =
-      web_view_->MainFrame()->MainWorldScriptContext();
+  v8::Local<v8::Context> context = main_frame()->MainWorldScriptContext();
   DCHECK(!context.IsEmpty());
 
   v8::Context::Scope context_scope(context);