--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -6041,55 +6041,54 @@ NS_IMETHODIMP
 nsGlobalWindow::SetFullScreen(bool aFullScreen)
 {
   FORWARD_TO_OUTER(SetFullScreen, (aFullScreen), NS_ERROR_NOT_INITIALIZED);
 
   return SetFullScreenInternal(aFullScreen, true);
 }
 
 nsresult
-nsGlobalWindow::SetFullScreenInternal(bool aFullScreen, bool aRequireTrust, gfx::VRHMDInfo* aHMD)
+nsGlobalWindow::SetFullScreenInternal(bool aFullScreen, bool aFullscreenMode,
+                                      gfx::VRHMDInfo* aHMD)
 {
   MOZ_ASSERT(IsOuterWindow());
 
   NS_ENSURE_TRUE(mDocShell, NS_ERROR_FAILURE);
 
-  // Only chrome can change our fullScreen mode, unless we're running in
-  // untrusted mode.
+  // Only chrome can change our fullscreen mode. Otherwise, the state
+  // can only be changed for DOM fullscreen.
   if (aFullScreen == FullScreen() ||
-      (aRequireTrust && !nsContentUtils::IsCallerChrome())) {
+      (aFullscreenMode && !nsContentUtils::IsCallerChrome())) {
     return NS_OK;
   }
 
   // SetFullScreen needs to be called on the root window, so get that
   // via the DocShell tree, and if we are not already the root,
   // call SetFullScreen on that window instead.
   nsCOMPtr<nsIDocShellTreeItem> rootItem;
   mDocShell->GetRootTreeItem(getter_AddRefs(rootItem));
   nsCOMPtr<nsPIDOMWindow> window = rootItem ? rootItem->GetWindow() : nullptr;
   if (!window)
     return NS_ERROR_FAILURE;
   if (rootItem != mDocShell)
-    return window->SetFullScreenInternal(aFullScreen, aRequireTrust, aHMD);
+    return window->SetFullScreenInternal(aFullScreen, aFullscreenMode, aHMD);
 
   // make sure we don't try to set full screen on a non-chrome window,
   // which might happen in embedding world
   if (mDocShell->ItemType() != nsIDocShellTreeItem::typeChrome)
     return NS_ERROR_FAILURE;
 
   // If we are already in full screen mode, just return.
   if (mFullScreen == aFullScreen)
     return NS_OK;
 
-  // If a fullscreen is originated from chrome, we are switching to
-  // the fullscreen mode, otherwise, we are entering DOM fullscreen.
   // Note that although entering DOM fullscreen could also cause
   // consequential calls to this method, those calls will be skipped
   // at the condition above.
-  if (aRequireTrust) {
+  if (aFullscreenMode) {
     mFullscreenMode = aFullScreen;
   } else {
     // If we are exiting from DOM fullscreen while we
     // initially make the window fullscreen because of
     // fullscreen mode, don't restore the window.
     if (!aFullScreen && mFullscreenMode) {
       return NS_OK;
     }

--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@@ -485,17 +485,17 @@ public:
   // Outer windows only.
   virtual bool DispatchCustomEvent(const nsAString& aEventName) override;
   bool DispatchResizeEvent(const mozilla::CSSIntSize& aSize);
 
   // Inner windows only.
   virtual void RefreshCompartmentPrincipal() override;
 
   // Outer windows only.
-  virtual nsresult SetFullScreenInternal(bool aIsFullScreen, bool aRequireTrust,
+  virtual nsresult SetFullScreenInternal(bool aIsFullscreen, bool aFullscreenMode,
                                          mozilla::gfx::VRHMDInfo *aHMD = nullptr) override;
   bool FullScreen() const;
 
   // Inner windows only.
   virtual void SetHasGamepadEventListener(bool aHasGamepad = true) override;
 
   // nsIInterfaceRequestor
   NS_DECL_NSIINTERFACEREQUESTOR

--- a/dom/base/nsPIDOMWindow.h
+++ b/dom/base/nsPIDOMWindow.h
@@ -458,25 +458,26 @@ public:
     if (!mMayHaveTouchEventListener) {
       mMayHaveTouchEventListener = true;
       MaybeUpdateTouchState();
     }
   }
 
   /**
    * Moves the top-level window into fullscreen mode if aIsFullScreen is true,
-   * otherwise exits fullscreen. If aRequireTrust is true, this method only
-   * changes window state in a context trusted for write.
+   * otherwise exits fullscreen. If aFullscreenMode is true, this method is
+   * called for fullscreen mode instead of DOM fullscreen, which means it can
+   * only change window state in a context trusted for write.
    *
    * If aHMD is not null, the window is made full screen on the given VR HMD
    * device instead of its currrent display.
    *
    * Outer windows only.
    */
-  virtual nsresult SetFullScreenInternal(bool aIsFullScreen, bool aRequireTrust,
+  virtual nsresult SetFullScreenInternal(bool aIsFullscreen, bool aFullscreenMode,
                                          mozilla::gfx::VRHMDInfo *aHMD = nullptr) = 0;
 
   /**
    * Call this to check whether some node (this window, its document,
    * or content in that document) has a mouseenter/leave event listener.
    */
   bool HasMouseEnterLeaveEventListeners()
   {