Blacklist force_compositing_mode in Vista.

content/browser/gpu/software_rendering_list.json

Index: content/browser/gpu/software_rendering_list.json
===================================================================
--- content/browser/gpu/software_rendering_list.json	(revision 177239)
+++ content/browser/gpu/software_rendering_list.json	(working copy)
@@ -75,7 +75,7 @@
 {
   "name": "software rendering list",
   // Please update the version number whenever you change this file.
-  "version": "4.10",
+  "version": "4.11",
   "entries": [
     {
       "id": 1,
@@ -968,6 +968,21 @@
       "blacklist": [
         "accelerated_video_decode"
       ]
+    },
+    {
+      "id": 65,
+      "description": "Force compositing mode is unstable in Win Vista.",
+      "cr_bugs": [170421],
+      "os": {
+        "type": "win",
+        "version": {
+          "op": "=",
+          "number": "6.0"
+        }
+      },
+      "blacklist": [
+        "force_compositing_mode"
+      ]
     }
   ]
 }