Disable force-compositing-mode on MacOSX earlier than 10.8

content/browser/gpu/software_rendering_list.json

 // Determines whether certain gpu-related features are blacklisted or not.
 // A valid software_rendering_list.json file are in the format of
 // {
 //   "version": "x.y",
 //   "entries": [
 //     { // entry 1
 //     },
 //     ...
 //     { // entry n
 //     }
@@ skipping 57 matching lines @@
 //
 // FLOAT includes "op" "value", and "value2".  "op" can be any of the
 // following values: "=", "<", "<=", ">", ">=", "any", "between".  "value2" is
 // only used if "op" is "between".  "value" is used for all "op" values except
 // "any". "value" and "value2" are valid float numbers.
 // INT is very much like FLOAT, except that the values need to be integers.
 
 {
   "name": "software rendering list",
   // Please update the version number whenever you change this file.
-  "version": "4.14",
+  "version": "4.15",
   "entries": [
     {
       "id": 1,
       "description": "ATI Radeon X1900 is not compatible with WebGL on the Mac.",
       "webkit_bugs": [47028],
       "os": {
         "type": "macosx"
       },
       "vendor_id": "0x1002",
       "device_id": ["0x7249"],
@@ skipping 894 matching lines @@
       "os": {
         "type": "win",
         "version": {
           "op": "=",
           "number": "6.0"
         }
       },
       "blacklist": [
         "force_compositing_mode"
       ]
+    },
+    {
+      "id": 66,
+      "description": "Force compositing mode is unstable in MacOSX earlier than 10.8.",
+      "cr_bugs": [174101],
+      "os": {
+        "type": "macosx",
+        "version": {
+          "op": "<",
+          "number": "10.8"
+        }
+      },
+      "blacklist": [
+        "force_compositing_mode"
+      ]
     }
   ]
 }