Move SearchProvider implementation into Blink and make it a no-op.

third_party/WebKit/Source/core/frame/External.idl

Index: third_party/WebKit/Source/core/frame/External.idl
diff --git a/third_party/WebKit/Source/core/frame/External.idl b/third_party/WebKit/Source/core/frame/External.idl
new file mode 100644
index 0000000000000000000000000000000000000000..977e4e005d6d68ba041e878014630ea3567b5423
--- /dev/null
+++ b/third_party/WebKit/Source/core/frame/External.idl
@@ -0,0 +1,9 @@
+// Copyright 2016 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.
+
+[NoInterfaceObject]
+interface External {
+  void AddSearchProvider();
+  void IsSearchProviderInstalled();
+};