Split web_view_internal_api and move part of it to extensions.

extensions/common/api/_api_features.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.
 
 // This features file defines extension APIs implemented under src/extensions.
 // See extensions/common/features/* to understand this file, in particular
 // feature.h, simple_feature.h, and base_feature_provider.h.
 //
 // Note that specifying "web_page", "blessed_web_page", or "all" as a context
 // type will require manually updating chrome/renderer/resources/dispatcher.cc.
@@ skipping 192 matching lines @@
     "extension_types": ["extension"],
     "location": "component"
   },
   "usb": {
     "dependencies": ["permission:usb"],
     "contexts": ["blessed_extension"]
   },
   "usbPrivate": {
     "channel": "dev",
     "contexts": ["webui"]
-  }
+  },
+  "webViewExperimentalInternal": [{
+    "internal": true,
+    "channel": "dev",
+    "contexts": ["blessed_extension"],
+    "dependencies": ["permission:webview"]
+  },
+  {
+    "internal": true,
+    "channel": "stable",
+    "contexts": ["blessed_extension"],
+    "dependencies": ["permission:webview"],
+    "whitelist": [
+      "8C3741E3AF0B93B6E8E0DDD499BB0B74839EA578",
+      "E703483CEF33DEC18B4B6DD84B5C776FB9182BDB",
+      "1A26E32DE447A17CBE5E9750CDBA78F58539B39C",
+      "59048028102D7B4C681DBC7BC6CD980C3DC66DA3"
+    ]
+  }],
+  "webViewInternal": [{
+    "internal": true,
+    "dependencies": ["permission:webview"],
+    "contexts": ["blessed_extension"]
+  }, {
+    // Component extensions can use the webViewInternal API from iframes.
+    "location": "component",
+    "internal": true,
+    "dependencies": ["permission:webview"],
+    "contexts": ["unblessed_extension"]
+  }]
 }