Add new extension APIs related to animation policy.

chrome/common/extensions/api/accessibility_private.json

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "accessibilityPrivate",
     "compiler_options": {
       "implemented_in": "chrome/browser/accessibility/accessibility_extension_api.h"
     },
@@ skipping 191 matching lines @@
         "description": "Enables or disables the accessibility extension api. This must be set to true before event listeners or getFocusedControl will work.",
         "parameters": [
           {
             "type": "boolean",
             "name": "enabled",
             "description": "True if accessibility support should be enabled."
           }
         ]
       },
       {
+        "name": "getImageAnimationPolicy",
+        "type": "function",
+        "description": "Get the policy for handling animated images in web contents.",
+        "parameters": [
+          {
+            "type": "function",
+            "name": "callback",
+            "parameters": [
+              {
+                "type": "string",

[dmazzoni, 2014/12/08 07:46:01]

Make the possible values for this type explicit using "enum":

"enum": ["allowed", "once", "none"]

...and the same below for setImageAnimationPolicy

+                "name": "policy"
+              }
+            ]
+          }
+        ]
+      },
+      {
+        "name": "setImageAnimationPolicy",
+        "type": "function",
+        "description": "Set the policy for handling animated images in web contents.",
+        "parameters": [
+          {
+            "type": "string",
+            "name": "policy",
+            "description": "The policy for animated images, Allowed, Once and None"
+          }
+        ]
+      },
+      {
         "name": "setNativeAccessibilityEnabled",
         "type": "function",
         "description": "Enables or disables native accessibility support. Once disabled, it is up to the calling extension to provide accessibility for web contents.",
         "parameters": [
           {
             "type": "boolean",
             "name": "enabled",
             "description": "True if native accessibility support should be enabled."
           }
         ]
@@ skipping 165 matching lines @@
           {
             "type": "boolean",
             "name": "makeAnnouncements",
             "description": "Whether to make introductory announcements."
           }
         ]
       }
     ]
   }
 ]