diff --git a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_dbg.json b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_dbg.json
index 66fb27f600..4a13c57c96 100644
--- a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_dbg.json
+++ b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS devices."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
diff --git a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_perf.json b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_perf.json
index a34dffa88e..45e86eba3e 100644
--- a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_perf.json
+++ b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_perf.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS devices."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
diff --git a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_rel.json b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_rel.json
index e7fbec6d70..e8c2d62861 100644
--- a/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_rel.json
+++ b/tools_webrtc/ios/internal.tryserver.webrtc/ios_arm64_rel.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS devices."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "dcheck_always_on=true",
     "goma_dir=\"$(goma_dir)\"",
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
index 242df5ff3d..8eeece96ff 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios32_sim_ios9_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 32-bit iOS simulators."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -19,7 +19,17 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 5",
-      "os": "9.3"
+      "os": "9.3",
+      "dimensions": [
+        {
+          "os": "Mac-10.12",
+          "pool": "Chrome"
+        },
+        {
+          "os": "Mac-10.13",
+          "pool": "Chrome"
+        }
+      ]
     }
   ]
 }
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
index a902cc1429..44a6063ca3 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios10_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -19,7 +19,17 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 6s",
-      "os": "10.3"
+      "os": "10.3",
+      "dimensions": [
+        {
+          "os": "Mac-10.12",
+          "pool": "Chrome"
+        },
+        {
+          "os": "Mac-10.13",
+          "pool": "Chrome"
+        }
+      ]
     }
   ]
 }
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
index 6804a60d2e..c145ddaf40 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios11_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -19,7 +19,17 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 7",
-      "os": "11.0"
+      "os": "11.0",
+      "dimensions": [
+        {
+          "os": "Mac-10.12",
+          "pool": "Chrome"
+        },
+        {
+          "os": "Mac-10.13",
+          "pool": "Chrome"
+        }
+      ]
     }
   ]
 }
diff --git a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
index 25eadbec03..2c0d62be4c 100644
--- a/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
+++ b/tools_webrtc/ios/tryserver.webrtc/ios64_sim_ios9_dbg.json
@@ -2,7 +2,7 @@
   "comments": [
     "Tests for 64-bit iOS simulators."
   ],
-  "xcode version": "9.0",
+  "xcode build version": "9C40b",
   "gn_args": [
     "goma_dir=\"$(goma_dir)\"",
     "is_component_build=false",
@@ -19,7 +19,17 @@
     {
       "include": "common_tests.json",
       "device type": "iPhone 6s",
-      "os": "9.3"
+      "os": "9.3",
+      "dimensions": [
+        {
+          "os": "Mac-10.12",
+          "pool": "Chrome"
+        },
+        {
+          "os": "Mac-10.13",
+          "pool": "Chrome"
+        }
+      ]
     }
   ]
 }