Add new extension APIs related to animation policy.

chrome/common/extensions/api/accessibility_features.json

Index: chrome/common/extensions/api/accessibility_features.json
diff --git a/chrome/common/extensions/api/accessibility_features.json b/chrome/common/extensions/api/accessibility_features.json
index 9e14bb89f3175e76feb79d83ffeb4412740ed1dc..750b2041692d97b8f2c7d133fbd7e94186ebfa64 100644
--- a/chrome/common/extensions/api/accessibility_features.json
+++ b/chrome/common/extensions/api/accessibility_features.json
@@ -5,7 +5,6 @@
 [
   {
     "namespace": "accessibilityFeatures",
-    "platforms": ["chromeos"],
     "description": "Use the <code>chrome.accessibilityFeatures</code> API to manage Chrome's accessibility features. This API relies on the <a href='types#ChromeSetting'>ChromeSetting prototype of the type API</a> for getting and setting individual accessibility features. In order to get feature states the extension must request <code>accessibilityFeatures.read</code> permission. For modifying feature state, the extension needs <code>accessibilityFeatures.modify</code> permission. Note that <code>accessibilityFeatures.modify</code> does not imply <code>accessibilityFeatures.read</code> permission.",
     "properties": {
       "spokenFeedback": {
@@ -42,6 +41,11 @@
         "$ref": "types.ChromeSetting",
         "description": "Virtual on-screen keyboard. The value indicates whether the feature is enabled or not. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.",
         "value": ["virtualKeyboard", {"type": "boolean"}]
+      },
+      "animationPolicy": {
+        "$ref": "types.ChromeSetting",
+        "description": "Policy for animated images. The value indicates how to handle animated images on web pages. The value indicates policy, one of allowd, once and none. <code>get()</code> requires <code>accessibilityFeatures.read</code> permission. <code>set()</code> and <code>clear()</code> require <code>accessibilityFeatures.modify</code> permission.",

[not at google - send to devlin, 2014/12/11 17:48:15]

The enum is self-documenting, so you don't need to spell out here "The value
indicates policy, one of allowd, once and none" etc, just leave out that
sentence.

[je_julie(Not used), 2014/12/12 13:15:45]

Done

+        "value": ["animationPolicy", {"type": "string", "enum": ["allowed", "once", "none"]}]

[not at google - send to devlin, 2014/12/11 17:48:15]

... but the enum is even better if you can document it. Note that I'm doing some
wrapping here, and you should too, otherwise it will be an awfully long line. It
will look like this:

"value": [
  "animationPolicy", {
    "type": "string",
    "enum": [{
      "value": "allowed".
      "description": "Images are allowed to animate."
    }, {
      "value": "once",
      "description": "...",
    }, {
      "value": "none",
      "description": "..."
    }]
  }
],

Also note that I think "never" might be a better word that "none" but I'll let
dmazzoni@ comment on that.

[je_julie(Not used), 2014/12/12 13:15:45]

I updated it.

       }
     }
   }