Add support for response header manipulation in Declarative WebRequest API

chrome/common/extensions/api/declarative_web_request.json

 // Copyright (c) 2012 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": "declarativeWebRequest",
     "documentation_permissions_required": ["declarative", "declarativeWebRequest"],
     "types": [
       {
@@ skipping 82 matching lines @@
             "type": "string", "enum": ["declarativeWebRequest.RemoveRequestHeader"],
             "nodoc": true
           },
           "name": {
             "type": "string",
             "description": "HTTP request header name (case-insensitive)."
           }
         }
       },
       {
+        "id": "declarativeWebRequest.AddResponseHeader",
+        "description": "Adds the response header to the response of this web request. As multiple response headers may share the same name, you need to first remove and then add a new response header in order to replace one.",
+        "type": "object",
+        "properties": {
+          "instanceType": {
+            "type": "string", "enum": ["declarativeWebRequest.AddResponseHeader"],
+            "nodoc": true
+          },
+          "name": {
+            "type": "string",
+            "description": "HTTP response header name."
+          },
+          "value": {
+            "type": "string",
+            "description": "HTTP response header value."
+          }
+        }
+      },
+      {
+        "id": "declarativeWebRequest.RemoveResponseHeader",
+        "description": "Removes all response headers of the specified names and values.",
+        "type": "object",
+        "properties": {
+          "instanceType": {
+            "type": "string", "enum": ["declarativeWebRequest.RemoveResponseHeader"],
+            "nodoc": true
+          },
+          "name": {
+            "type": "string",
+            "description": "HTTP request header name (case-insensitive)."
+          },
+          "value": {
+            "type": "string",
+            "description": "HTTP request header value (case-insensitive).",
+            "optional": true
+          }
+        }
+      },
+      {
         "id": "declarativeWebRequest.IgnoreRules",
         "description": "Masks all rules that match the specified criteria.",
         "type": "object",
         "properties": {
           "instanceType": {
             "type": "string", "enum": ["declarativeWebRequest.IgnoreRules"],
             "nodoc": true
           },
           "lowerPriorityThan": {
             "type": "integer",
             "description": "If set, rules with a lower priority than the specified value are ignored. This boundary is not persited, it affects only rules and their actions of the same network request stage. TODO(battre): Explain network request stages."
           }
         }
       }
     ],
     "functions": [
     ],
     "events": [
       {
         "name": "onRequest",
         "options": {
           "supportsListeners": false,
           "supportsRules": true,
           "conditions": ["declarativeWebRequest.RequestMatcher"],
           "actions": [
+            "declarativeWebRequest.AddResponseHeader",
             "declarativeWebRequest.CancelRequest",
             "declarativeWebRequest.RedirectRequest",
             "declarativeWebRequest.RedirectToTransparentImage",
             "declarativeWebRequest.RedirectToEmptyDocument",
             "declarativeWebRequest.SetRequestHeader",
             "declarativeWebRequest.RemoveRequestHeader",
+            "declarativeWebRequest.RemoveResponseHeader",
             "declarativeWebRequest.IgnoreRules"
           ]
         }
       }
     ]
   }
 ]