Cleanup blimp/client/core code organization.

blimp/client/core/switches/BUILD.gn

+# 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.
+
+if (is_android) {
+  import("//build/config/android/config.gni")
+  import("//build/config/android/rules.gni")
+}
+
+source_set("switches") {
+  visibility = [
+    "//blimp/client/*",
+    "//blimp/engine:browser_tests",
+  ]
+
+  sources = [
+    "blimp_client_switches.cc",
+    "blimp_client_switches.h",
+  ]
+}
+
+if (is_android) {
+  android_library("switches_java") {
+    visibility = [ "//blimp/client/*" ]
+
+    java_files =
+        [ "android/java/src/org/chromium/blimp/core/BlimpClientSwitches.java" ]
+  }
+}