cc: Remove all blimp code from cc.

cc/proto/region.proto

Index: cc/proto/region.proto
diff --git a/cc/proto/region.proto b/cc/proto/region.proto
deleted file mode 100644
index 0524e921ada30770283d5eb60f08483640cf0416..0000000000000000000000000000000000000000
--- a/cc/proto/region.proto
+++ /dev/null
@@ -1,15 +0,0 @@
-// Copyright 2015 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.
-
-syntax = "proto2";
-
-import "rect.proto";
-
-option optimize_for = LITE_RUNTIME;
-
-package cc.proto;
-
-message Region {
-  repeated Rect rects = 1;
-}