diff --git a/browser/base/content/test/performance/browser_startup_syncIPC.js b/browser/base/content/test/performance/browser_startup_syncIPC.js
index 245e02cb6fbf..6bef625bc508 100644
--- a/browser/base/content/test/performance/browser_startup_syncIPC.js
+++ b/browser/base/content/test/performance/browser_startup_syncIPC.js
@@ -27,7 +27,7 @@ const startupPhases = {
   "before first paint": [
     {
       name: "PLayerTransaction::Msg_GetTextureFactoryIdentifier",
-      condition: MAC || LINUX,
+      condition: (MAC && !WEBRENDER) || LINUX,
       maxCount: 1,
     },
     {
@@ -40,6 +40,11 @@ const startupPhases = {
       condition: WIN && WEBRENDER,
       maxCount: 2,
     },
+    {
+      name: "PWebRenderBridge::Msg_EnsureConnected",
+      condition: MAC && WEBRENDER,
+      maxCount: 1,
+    },
     {
       // bug 1373773
       name: "PCompositorBridge::Msg_NotifyChildCreated",
diff --git a/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-lr.html.ini b/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-lr.html.ini
index 2fce8b0ee701..2333107b45fa 100644
--- a/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-lr.html.ini
+++ b/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-lr.html.ini
@@ -7,17 +7,17 @@
 
   [.grid 1]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
  
   [.grid 5]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
  
   [.grid 4]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
  
   [.grid 6]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
  
diff --git a/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-rl.html.ini b/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-rl.html.ini
index 57312ecd8bc8..ced408a08764 100644
--- a/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-rl.html.ini
+++ b/testing/web-platform/meta/css/css-grid/layout-algorithm/grid-minimum-contribution-baseline-shim-vertical-rl.html.ini
@@ -10,13 +10,13 @@
 
   [.grid 5]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
  
   [.grid 4]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL
 
   [.grid 6]
     expected:
-      if not webrender and (os == "mac"): FAIL
+      if (os == "mac"): FAIL