Remove all blimp client code.

blimp/client/support/session/BUILD.gn

Index: blimp/client/support/session/BUILD.gn
diff --git a/blimp/client/support/session/BUILD.gn b/blimp/client/support/session/BUILD.gn
deleted file mode 100644
index ba6b59a63cc04e4f6b858df87769af9d05f74d12..0000000000000000000000000000000000000000
--- a/blimp/client/support/session/BUILD.gn
+++ /dev/null
@@ -1,24 +0,0 @@
-# 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("session") {
-  sources = [
-    "blimp_default_identity_provider.cc",
-    "blimp_default_identity_provider.h",
-  ]
-
-  public_deps = [
-    "//base",
-    "//google_apis:google_apis",
-  ]
-
-  deps = [
-    "//blimp/client/public:public_headers",
-  ]
-}