Add "panel_fitting" GPU feature type and use it for mirror mode.

content/browser/gpu/software_rendering_list.json

Index: content/browser/gpu/software_rendering_list.json
diff --git a/content/browser/gpu/software_rendering_list.json b/content/browser/gpu/software_rendering_list.json
index d5d4c0ddfd64ff74058ee12d2eb1912b6dc8580c..a4f08a039fc8cba01d4ca08313ddc996a673b626 100644
--- a/content/browser/gpu/software_rendering_list.json
+++ b/content/browser/gpu/software_rendering_list.json
@@ -41,7 +41,7 @@
 // 19. "blacklist" is a list of gpu feature strings, valid values include
 //     "accelerated_2d_canvas", "accelerated_compositing", "webgl",
 //     "multisampling", "flash_3d", "flash_stage3d", "texture_sharing",
-//     "accelerated_video_decode", and "all".
+//     "accelerated_video_decode", "panel_fitting", and "all".
 //     This field is mandatory.
 // 20. "description" has the description of the entry.
 // 21. "webkit_bugs" is an array of associated webkit bug numbers.
@@ -74,7 +74,7 @@
 {
   "name": "software rendering list",
   // Please update the version number whenever you change this file.
-  "version": "3.8",
+  "version": "3.9",
   "entries": [
     {
       "id": 1,
@@ -855,6 +855,22 @@
         "flash_3d",
         "flash_stage3d"
       ]
+    },
+    {
+      "id": 57,
+      "description": "Enable panel fitting capability on ChromeOS only on Ivy Bridge Graphics Controller.",
+      "exceptions": [
+        {
+          "os": {
+            "type": "chromeos"
+          },
+          "vendor_id": "0x8086",
+          "device_id": ["0x0166"]
+        }
+      ],
+      "blacklist": [
+        "panel_fitting"
+      ]
     }
   ]
 }