Makes the IME APIs available for beta/stable channels.

BUG=607425,517773

Review-Url: https://codereview.chromium.org/1925983002
Cr-Commit-Position: refs/heads/master@{#414313}

chrome/common/extensions/api/_permission_features.json

@@ -452,15 +452,11 @@
     "channel": "trunk",
     "extension_types": ["extension"]
   },
-  "input": [{
+  "input": {
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app"],
-    "platforms": ["chromeos"]
-  }, {
-    "channel": "dev",
-    "extension_types": ["extension", "legacy_packaged_app"],
-    "platforms": ["win", "linux"]
-  }],
+    "platforms": ["chromeos", "win", "linux"]
+  },
   "inputMethodPrivate": [{
     "channel": "stable",
     "extension_types": ["extension", "legacy_packaged_app", "platform_app"],