Bug 1562264 - Propagate remote/fission flags from parent to child for content window.open() calls, r=kmag

Differential Revision: https://phabricator.services.mozilla.com/D40836

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

dom/ipc/ContentParent.cpp

@@ -4696,11 +4696,10 @@ mozilla::ipc::IPCResult ContentParent::CommonCreateWindow(
 
 {
   // The content process should never be in charge of computing whether or
-  // not a window should be private or remote - the parent will do that.
+  // not a window should be private - the parent will do that.
   const uint32_t badFlags = nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW |
                             nsIWebBrowserChrome::CHROME_NON_PRIVATE_WINDOW |
-                            nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME |
-                            nsIWebBrowserChrome::CHROME_REMOTE_WINDOW;
+                            nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME;
   if (!!(aChromeFlags & badFlags)) {
     return IPC_FAIL(this, "Forbidden aChromeFlags passed");
   }
@@ -4709,6 +4708,20 @@ mozilla::ipc::IPCResult ContentParent::CommonCreateWindow(
   BrowserHost* thisBrowserHost =
       thisBrowserParent ? thisBrowserParent->GetBrowserHost() : nullptr;
   MOZ_ASSERT(!thisBrowserParent == !thisBrowserHost);
+
+  // The content process should not have set its remote or fission flags if the
+  // parent doesn't also have these set.
+  if (thisBrowserHost) {
+    nsCOMPtr<nsILoadContext> context = thisBrowserHost->GetLoadContext();
+
+    if (context->UseRemoteTabs() !=
+            !!(aChromeFlags & nsIWebBrowserChrome::CHROME_REMOTE_WINDOW) ||
+        context->UseRemoteSubframes() !=
+            !!(aChromeFlags & nsIWebBrowserChrome::CHROME_FISSION_WINDOW)) {
+      return IPC_FAIL(this, "Unexpected aChromeFlags passed");
+    }
+  }
+
   nsCOMPtr<nsIContent> frame;
   if (thisBrowserParent) {
     frame = thisBrowserParent->GetOwnerElement();

toolkit/components/windowwatcher/nsWindowWatcher.cpp

@@ -691,6 +691,20 @@ nsresult nsWindowWatcher::OpenWindowInternal(
       MOZ_ASSERT(XRE_IsParentProcess());
       chromeFlags |= nsIWebBrowserChrome::CHROME_OPENAS_DIALOG;
     }
+
+    // Propagate the remote & fission status of the parent window, if available,
+    // to the child.
+    if (parentWindow) {
+      auto* docShell = nsDocShell::Cast(parentWindow->GetDocShell());
+
+      if (docShell->UseRemoteTabs()) {
+        chromeFlags |= nsIWebBrowserChrome::CHROME_REMOTE_WINDOW;
+      }
+
+      if (docShell->UseRemoteSubframes()) {
+        chromeFlags |= nsIWebBrowserChrome::CHROME_FISSION_WINDOW;
+      }
+    }
   }
 
   SizeSpec sizeSpec;
@@ -2472,6 +2486,7 @@ int32_t nsWindowWatcher::GetWindowOpenLocation(nsPIDOMWindowOuter* aParent,
       // which might have been automatically flipped by Gecko.
       int32_t uiChromeFlags = aChromeFlags;
       uiChromeFlags &= ~(nsIWebBrowserChrome::CHROME_REMOTE_WINDOW |
+                         nsIWebBrowserChrome::CHROME_FISSION_WINDOW |
                          nsIWebBrowserChrome::CHROME_PRIVATE_WINDOW |
                          nsIWebBrowserChrome::CHROME_NON_PRIVATE_WINDOW |
                          nsIWebBrowserChrome::CHROME_PRIVATE_LIFETIME);

toolkit/components/windowwatcher/test/browser_new_content_window_chromeflags.js

@@ -282,9 +282,17 @@ add_task(async function test_new_remote_window_flags() {
       // as part of the BrowserChild, so we have to check those too.
       let contentChromeFlags = await getContentChromeFlags(win);
       assertContentFlags(contentChromeFlags);
-      Assert.ok(
-        !(contentChromeFlags & Ci.nsIWebBrowserChrome.CHROME_REMOTE_WINDOW),
-        "Should not be remote in the content process."
+
+      Assert.equal(
+        parentChromeFlags & Ci.nsIWebBrowserChrome.CHROME_REMOTE_WINDOW,
+        contentChromeFlags & Ci.nsIWebBrowserChrome.CHROME_REMOTE_WINDOW,
+        "Should have matching remote value in parent and content"
+      );
+
+      Assert.equal(
+        parentChromeFlags & Ci.nsIWebBrowserChrome.CHROME_FISSION_WINDOW,
+        contentChromeFlags & Ci.nsIWebBrowserChrome.CHROME_FISSION_WINDOW,
+        "Should have matching fission value in parent and content"
       );
 
       await BrowserTestUtils.closeWindow(win);