Bug 1584492 - Add mPIPWindow to nsWidgetInitData and set it for PIP window on Linux/Gtk, r=mats

Differential Revision: https://phabricator.services.mozilla.com/D47409

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

Author: stransky

widget/nsWidgetInitData.h

@@ -111,7 +111,8 @@ struct nsWidgetInitData {
         mSupportTranslucency(false),
         mMouseTransparent(false),
         mHasRemoteContent(false),
-        mAlwaysOnTop(false) {}
+        mAlwaysOnTop(false),
+        mPIPWindow(false) {}
 
   nsWindowType mWindowType;
   nsBorderStyle mBorderStyle;
@@ -137,6 +138,8 @@ struct nsWidgetInitData {
   bool mMouseTransparent;
   bool mHasRemoteContent;
   bool mAlwaysOnTop;
+  // Is PictureInPicture window
+  bool mPIPWindow;
 };
 
 #endif  // nsWidgetInitData_h__

xpfe/appshell/nsAppShellService.cpp

@@ -624,6 +624,21 @@ nsresult nsAppShellService::JustCreateTopWindow(
   if (aChromeMask & nsIWebBrowserChrome::CHROME_ALWAYS_ON_TOP)
     widgetInitData.mAlwaysOnTop = true;
 
+#ifdef MOZ_WIDGET_GTK
+  // Linux/Gtk PIP window support. It's Chrome Toplevel window, always on top
+  // and without any bar.
+  uint32_t pipMask = nsIWebBrowserChrome::CHROME_ALWAYS_ON_TOP |
+                     nsIWebBrowserChrome::CHROME_OPENAS_CHROME;
+  uint32_t barMask = nsIWebBrowserChrome::CHROME_MENUBAR |
+                     nsIWebBrowserChrome::CHROME_TOOLBAR |
+                     nsIWebBrowserChrome::CHROME_LOCATIONBAR |
+                     nsIWebBrowserChrome::CHROME_STATUSBAR;
+  if (widgetInitData.mWindowType == eWindowType_toplevel &&
+      ((aChromeMask & pipMask) == pipMask) && !(aChromeMask & barMask)) {
+    widgetInitData.mPIPWindow = true;
+  }
+#endif
+
 #ifdef XP_MACOSX
   // Mac OS X sheet support
   // Adding CHROME_OPENAS_CHROME to sheetMask makes modal windows opened from