Build with GN on CT bots.

infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json

Index: infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json
diff --git a/infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json b/infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json
index 937e4f1d854abd61d39e4741ca5caeb264228247..8b36687f618385b1e33b1b3e2089ab4764c8a0ca 100644
--- a/infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json
+++ b/infra/bots/recipes/swarm_ct_skps.expected/CT_IMG_DECODE_10k_SKPs_Trybot.json
@@ -143,18 +143,38 @@
   },
   {
     "cmd": [
-      "make",
-      "tools"
+      "[CUSTOM_/_B_WORK]/skia/bin/fetch-gn"
     ],
     "cwd": "[CUSTOM_/_B_WORK]/skia",
     "env": {
-      "BUILDTYPE": "Debug",
-      "CHROME_HEADLESS": "1",
-      "CHROME_PATH": "[SLAVE_BUILD]/src",
-      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]",
-      "SKIA_OUT": "[SLAVE_BUILD]/out"
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "name": "fetch-gn"
+  },
+  {
+    "cmd": [
+      "gn",
+      "gen",
+      "[SLAVE_BUILD]/out/Debug",
+      "--args=cc=\"gcc\" cxx=\"g++\""
+    ],
+    "cwd": "[CUSTOM_/_B_WORK]/skia",
+    "env": {
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]"
+    },
+    "name": "gn gen"
+  },
+  {
+    "cmd": [
+      "ninja",
+      "-C",
+      "[SLAVE_BUILD]/out/Debug"
+    ],
+    "cwd": "[CUSTOM_/_B_WORK]/skia",
+    "env": {
+      "PATH": "%(PATH)s:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]:RECIPE_PACKAGE_REPO[depot_tools]"
     },
-    "name": "build tools"
+    "name": "ninja"
   },
   {
     "cmd": [