Add Chrome IME extensions to the whitelisted extensions for app.window.alpha

This allows ime extensions creat window with proper shadow through css and a round button as in this mock:
https://folio.googleplex.com/chromeinput/final/voice#%2F00%20VK_start%20to%20speak.png

BUG=425539

Review URL: https://codereview.chromium.org/643283002

Cr-Commit-Position: refs/heads/master@{#300697}

chrome/browser/resources/chromeos/input_method/google_xkb_manifest.json

@@ -7,6 +7,7 @@
   "key": "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC7C0oB6YTnf69uhWnVTZl5TB/psHrJXgIPLYchFb0whlVCG8fqMo9lW/oxBmZXZ3N8T7zZrdYI/SUjoc9I5R/dMVVD2q4iKox+x7xlTbqSdVeOb6b9ZVJ24pLbO1L7feSNSBgR0t61jrC2eY/gf78h7w58UEQBPFT2mUxhhwodyQIDAQAB",
   "permissions": [
     "app.window.ime",
+    "app.window.alpha",
     "input",
     "inputMethodPrivate",
     "virtualKeyboardPrivate",

chrome/browser/resources/chromeos/input_method/xkb_manifest.json

@@ -6,6 +6,7 @@
   "default_locale": "en",
   "permissions": [
     "app.window.ime",
+    "app.window.alpha",
     "input",
     "metricsPrivate",
     "accessibilityFeatures.read"

extensions/browser/api/app_window/app_window_api.cc

@@ -250,6 +250,8 @@ bool AppWindowCreateFunction::RunAsync() {
       const char* whitelist[] = {
 #if defined(OS_CHROMEOS)
         "B58B99751225318C7EB8CF4688B5434661083E07",  // http://crbug.com/410550
+        "06BE211D5F014BAB34BC22D9DDA09C63A81D828E",  // http://crbug.com/425539
+        "F94EE6AB36D6C6588670B2B01EB65212D9C64E33",
 #endif
         "0F42756099D914A026DADFA182871C015735DD95",  // http://crbug.com/323773
         "2D22CDB6583FD0A13758AEBE8B15E45208B4E9A7",

extensions/common/api/_permission_features.json

@@ -52,6 +52,14 @@
         "F16F23C83C5F6DAD9B65A120448B34056DD80691",
         "0F585FB1D0FDFBEBCE1FEB5E9DFFB6DA476B8C9B"
       ]
+    },
+    {
+      "channel": "stable",
+      "extension_types": ["extension"],
+      "whitelist": [
+        "06BE211D5F014BAB34BC22D9DDA09C63A81D828E",  // http://crbug.com/425539
+        "F94EE6AB36D6C6588670B2B01EB65212D9C64E33"
+      ]
     }
   ],
   "app.window.shape": {

extensions/common/permissions/extensions_api_permissions.cc

@@ -51,6 +51,7 @@ std::vector<APIPermissionInfo*> ExtensionsAPIPermissions::GetAllPermissions()
       {APIPermission::kFullscreen, "app.window.fullscreen"},
       {APIPermission::kHid, "hid", APIPermissionInfo::kFlagNone,
        IDS_EXTENSION_PROMPT_WARNING_HID, PermissionMessage::kHid},
+      {APIPermission::kImeWindowEnabled, "app.window.ime"},
       {APIPermission::kOverrideEscFullscreen,
        "app.window.fullscreen.overrideEsc"},
       {APIPermission::kPower, "power"},
@@ -92,7 +93,6 @@ std::vector<APIPermissionInfo*> ExtensionsAPIPermissions::GetAllPermissions()
       {APIPermission::kWebView, "webview",
        APIPermissionInfo::kFlagCannotBeOptional},
       {APIPermission::kWindowShape, "app.window.shape"},
-      {APIPermission::kImeWindowEnabled, "app.window.ime"},
   };
 
   std::vector<APIPermissionInfo*> permissions;