Pass opener ID in command line

atom/browser/lib/guest-window-manager.coffee

@@ -30,12 +30,13 @@ createGuest = (embedder, url, frameName, options) ->
     guest.loadURL url
     return guest.id
 
+  # Remember the embedder window's id.
+  options.webPreferences ?= {}
+  options.webPreferences.openerId = BrowserWindow.fromWebContents(embedder)?.id
+
   guest = new BrowserWindow(options)
   guest.loadURL url
 
-  # Remember the embedder, will be used by window.opener methods.
-  v8Util.setHiddenValue guest.webContents, 'embedder', embedder
-
   # When |embedder| is destroyed we should also destroy attached guest, and if
   # guest is closed by user then we should prevent |embedder| from double
   # closing guest.
@@ -83,10 +84,3 @@ ipcMain.on 'ATOM_SHELL_GUEST_WINDOW_MANAGER_WINDOW_POSTMESSAGE', (event, guestId
 
 ipcMain.on 'ATOM_SHELL_GUEST_WINDOW_MANAGER_WEB_CONTENTS_METHOD', (event, guestId, method, args...) ->
   BrowserWindow.fromId(guestId)?.webContents?[method] args...
-
-ipcMain.on 'ATOM_SHELL_GUEST_WINDOW_MANAGER_GET_OPENER_ID', (event) ->
-  embedder = v8Util.getHiddenValue event.sender, 'embedder'
-  openerId = null
-  if embedder?
-    openerId = BrowserWindow.fromWebContents(embedder)?.id
-  event.returnValue = openerId

atom/browser/web_contents_preferences.cc

@@ -132,6 +132,12 @@ void WebContentsPreferences::AppendExtraCommandLineSwitches(
   if (web_preferences.GetInteger(options::kGuestInstanceID, &guest_instance_id))
       command_line->AppendSwitchASCII(switches::kGuestInstanceID,
                                       base::IntToString(guest_instance_id));
+
+  // Pass the opener's window id.
+  int opener_id;
+  if (web_preferences.GetInteger(options::kOpenerID, &opener_id))
+      command_line->AppendSwitchASCII(switches::kOpenerID,
+                                      base::IntToString(opener_id));
 }
 
 // static

atom/common/options_switches.cc

@@ -91,6 +91,9 @@ const char kPageVisibility[] = "pageVisibility";
 // Enable DirectWrite on Windows.
 const char kDirectWrite[] = "directWrite";
 
+// Opener window's ID.
+const char kOpenerID[] = "openerId";
+
 // Web runtime features.
 const char kExperimentalFeatures[]       = "experimentalFeatures";
 const char kExperimentalCanvasFeatures[] = "experimentalCanvasFeatures";
@@ -143,6 +146,7 @@ const char kExperimentalCanvasFeatures[] = "experimental-canvas-features";
 const char kOverlayScrollbars[]          = "overlay-scrollbars";
 const char kSharedWorker[]               = "shared-worker";
 const char kPageVisibility[]             = "page-visiblity";
+const char kOpenerID[]                   = "opener-id";
 
 }  // namespace switches
 

atom/common/options_switches.h

@@ -52,6 +52,7 @@ extern const char kExperimentalCanvasFeatures[];
 extern const char kOverlayScrollbars[];
 extern const char kSharedWorker[];
 extern const char kPageVisibility[];
+extern const char kOpenerID[];
 
 }   // namespace options
 
@@ -81,6 +82,7 @@ extern const char kExperimentalCanvasFeatures[];
 extern const char kOverlayScrollbars[];
 extern const char kSharedWorker[];
 extern const char kPageVisibility[];
+extern const char kOpenerID[];
 
 }  // namespace switches
 

atom/renderer/lib/init.coffee

@@ -30,6 +30,9 @@ for arg in process.argv
   if arg.indexOf('--guest-instance-id=') == 0
     # This is a guest web view.
     process.guestInstanceId = parseInt arg.substr(arg.indexOf('=') + 1)
+  else if arg.indexOf('--opener-id=') == 0
+    # This is a guest BrowserWindow.
+    process.openerId = parseInt arg.substr(arg.indexOf('=') + 1)
   else if arg.indexOf('--node-integration=') == 0
     nodeIntegration = arg.substr arg.indexOf('=') + 1
   else if arg.indexOf('--preload=') == 0

atom/renderer/lib/override.coffee

@@ -91,8 +91,8 @@ window.confirm = (message, title='') ->
 window.prompt = ->
   throw new Error('prompt() is and will not be supported.')
 
-openerId = ipcRenderer.sendSync 'ATOM_SHELL_GUEST_WINDOW_MANAGER_GET_OPENER_ID'
-window.opener = BrowserWindowProxy.getOrCreate(openerId) if openerId?
+if process.openerId?
+  window.opener = BrowserWindowProxy.getOrCreate process.openerId
 
 ipcRenderer.on 'ATOM_SHELL_GUEST_WINDOW_POSTMESSAGE', (event, sourceId, message, sourceOrigin) ->
   # Manually dispatch event instead of using postMessage because we also need to