Bug 1620657 - Add `CanonicalBrowsingContext::GetParentProcessWidgetContaining()` r=nika,tnikkel

Differential Revision: https://phabricator.services.mozilla.com/D67683

--HG--
extra : moz-landing-system : lando

docshell/base/CanonicalBrowsingContext.cpp

@@ -16,6 +16,8 @@
 #include "mozilla/ipc/ProtocolUtils.h"
 #include "mozilla/NullPrincipal.h"
 
+#include "nsGlobalWindowOuter.h"
+
 using namespace mozilla::ipc;
 
 extern mozilla::LazyLogModule gAutoplayPermissionLog;
@@ -122,6 +124,28 @@ WindowGlobalParent* CanonicalBrowsingContext::GetCurrentWindowGlobal() const {
   return static_cast<WindowGlobalParent*>(GetCurrentWindowContext());
 }
 
+already_AddRefed<nsIWidget>
+CanonicalBrowsingContext::GetParentProcessWidgetContaining() {
+  // If our document is loaded in-process, such as chrome documents, get the
+  // widget directly from our outer window. Otherwise, try to get the widget
+  // from the toplevel content's browser's element.
+  nsCOMPtr<nsIWidget> widget;
+  if (nsGlobalWindowOuter* window = nsGlobalWindowOuter::Cast(GetDOMWindow())) {
+    widget = window->GetNearestWidget();
+  } else if (Element* topEmbedder = Top()->GetEmbedderElement()) {
+    widget = nsContentUtils::WidgetForContent(topEmbedder);
+    if (!widget) {
+      widget = nsContentUtils::WidgetForDocument(topEmbedder->OwnerDoc());
+    }
+  }
+
+  if (widget) {
+    widget = widget->GetTopLevelWidget();
+  }
+
+  return widget.forget();
+}
+
 already_AddRefed<WindowGlobalParent>
 CanonicalBrowsingContext::GetEmbedderWindowGlobal() const {
   uint64_t windowId = GetEmbedderInnerWindowId();

docshell/base/CanonicalBrowsingContext.h

@@ -61,6 +61,8 @@ class CanonicalBrowsingContext final : public BrowsingContext {
   // The current active WindowGlobal.
   WindowGlobalParent* GetCurrentWindowGlobal() const;
 
+  already_AddRefed<nsIWidget> GetParentProcessWidgetContaining();
+
   already_AddRefed<WindowGlobalParent> GetEmbedderWindowGlobal() const;
 
   nsISHistory* GetSessionHistory();