prevent double-adding a WebContents to view

atom/browser/api/atom_api_web_contents_view.cc

@@ -6,6 +6,7 @@
 
 #include "atom/browser/api/atom_api_web_contents.h"
 #include "brightray/browser/inspectable_web_contents_view.h"
+#include "content/public/browser/web_contents_user_data.h"
 #include "native_mate/dictionary.h"
 
 #if defined(OS_MACOSX)
@@ -14,6 +15,27 @@
 
 #include "atom/common/node_includes.h"
 
+namespace {
+
+// Used to indicate whether a WebContents already has a view.
+class WebContentsViewRelay
+    : public content::WebContentsUserData<WebContentsViewRelay> {
+ public:
+  ~WebContentsViewRelay() override {}
+
+ private:
+  explicit WebContentsViewRelay(content::WebContents* contents) {}
+  friend class content::WebContentsUserData<WebContentsViewRelay>;
+
+  atom::api::WebContentsView* view_ = nullptr;
+
+  DISALLOW_COPY_AND_ASSIGN(WebContentsViewRelay);
+};
+
+}  // namespace
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(WebContentsViewRelay);
+
 namespace atom {
 
 namespace api {
@@ -36,6 +58,7 @@ WebContentsView::WebContentsView(v8::Isolate* isolate,
   // On other platforms the View is managed by InspectableWebContents.
   set_delete_view(false);
 #endif
+  WebContentsViewRelay::CreateForWebContents(web_contents->web_contents());
   api_web_contents_->AddObserver(this);
 }
 
@@ -52,12 +75,23 @@ void WebContentsView::OnCloseContents() {
 mate::WrappableBase* WebContentsView::New(
     mate::Arguments* args,
     mate::Handle<WebContents> web_contents) {
+  // Currently we only support InspectableWebContents, e.g. the WebContents
+  // created by users directly. To support devToolsWebContents we need to create
+  // a wrapper view.
   if (!web_contents->managed_web_contents()) {
     const char* error = "The WebContents must be created by user";
     args->isolate()->ThrowException(
         v8::Exception::Error(mate::StringToV8(args->isolate(), error)));
     return nullptr;
   }
+  // Check if the WebContents has already been added to a view.
+  if (WebContentsViewRelay::FromWebContents(web_contents->web_contents())) {
+    const char* error = "The WebContents has already been added to a View";
+    args->isolate()->ThrowException(
+        v8::Exception::Error(mate::StringToV8(args->isolate(), error)));
+    return nullptr;
+  }
+  // Constructor call.
   auto* view = new WebContentsView(args->isolate(), web_contents,
                                    web_contents->managed_web_contents());
   view->InitWith(args->isolate(), args->GetThis());