Bug 1603889 - Make ScrollbarsProp::SetVisible do nothing, and minor cleanup of surrounding code. r=smaug

This removes another dead caller of nsContentUtils::SetScrollbarVisibility.

Plus, before these patches, nsContentUtils::SetScrollbarVisibility didn't
invalidate layout in any way, so it's not like it'd work, even if the chrome
code would set the preference (which it doesn't).

Differential Revision: https://phabricator.services.mozilla.com/D57185

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

dom/base/BarProps.cpp

@@ -201,34 +201,8 @@ bool ScrollbarsProp::GetVisible(CallerType aCallerType, ErrorResult& aRv) {
   return pref != ScrollbarPreference::Never;
 }
 
-void ScrollbarsProp::SetVisible(bool aVisible, CallerType aCallerType,
-                                ErrorResult& aRv) {
-  if (aCallerType != CallerType::System) {
-    return;
-  }
-
-  /* Scrollbars, unlike the other barprops, implement visibility directly
-     rather than handing off to the superclass (and from there to the
-     chrome window) because scrollbar visibility uniquely applies only
-     to the window making the change (arguably. it does now, anyway.)
-     and because embedding apps have no interface for implementing this
-     themselves, and therefore the implementation must be internal. */
-
-  nsContentUtils::SetScrollbarsVisibility(mDOMWindow->GetDocShell(), aVisible);
-
-  /* Notably absent is the part where we notify the chrome window using
-     GetBrowserChrome()->SetChromeFlags(). Given the possibility of multiple
-     DOM windows (multiple top-level windows, even) within a single
-     chrome window, the historical concept of a single "has scrollbars"
-     flag in the chrome is inapplicable, and we can't tell at this level
-     whether we represent the particular DOM window that makes this decision
-     for the chrome.
-
-     So only this object (and its corresponding DOM window) knows whether
-     scrollbars are visible. The corresponding chrome window will need to
-     ask (one of) its DOM window(s) when it needs to know about scrollbar
-     visibility, rather than caching its own copy of that information.
-  */
+void ScrollbarsProp::SetVisible(bool aVisible, CallerType, ErrorResult&) {
+  /* Do nothing */
 }
 
 }  // namespace dom

dom/base/BarProps.h

@@ -38,8 +38,7 @@ class BarProp : public nsISupports, public nsWrapperCache {
 
   nsPIDOMWindowInner* GetParentObject() const;
 
-  virtual JSObject* WrapObject(JSContext* aCx,
-                               JS::Handle<JSObject*> aGivenProto) override;
+  JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) final;
 
   virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) = 0;
   virtual void SetVisible(bool aVisible, CallerType aCallerType,
@@ -63,9 +62,9 @@ class MenubarProp final : public BarProp {
   explicit MenubarProp(nsGlobalWindowInner* aWindow);
   virtual ~MenubarProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 // Script "toolbar" object
@@ -74,9 +73,9 @@ class ToolbarProp final : public BarProp {
   explicit ToolbarProp(nsGlobalWindowInner* aWindow);
   virtual ~ToolbarProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 // Script "locationbar" object
@@ -85,9 +84,9 @@ class LocationbarProp final : public BarProp {
   explicit LocationbarProp(nsGlobalWindowInner* aWindow);
   virtual ~LocationbarProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 // Script "personalbar" object
@@ -96,9 +95,9 @@ class PersonalbarProp final : public BarProp {
   explicit PersonalbarProp(nsGlobalWindowInner* aWindow);
   virtual ~PersonalbarProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 // Script "statusbar" object
@@ -107,9 +106,9 @@ class StatusbarProp final : public BarProp {
   explicit StatusbarProp(nsGlobalWindowInner* aWindow);
   virtual ~StatusbarProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 // Script "scrollbars" object
@@ -118,9 +117,9 @@ class ScrollbarsProp final : public BarProp {
   explicit ScrollbarsProp(nsGlobalWindowInner* aWindow);
   virtual ~ScrollbarsProp();
 
-  virtual bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
-  virtual void SetVisible(bool aVisible, CallerType aCallerType,
-                          ErrorResult& aRv) override;
+  bool GetVisible(CallerType aCallerType, ErrorResult& aRv) override;
+  void SetVisible(bool aVisible, CallerType aCallerType,
+                  ErrorResult& aRv) override;
 };
 
 }  // namespace dom