cc: Remove all blimp code from cc.

cc/proto/layer_position_constraint.proto

Index: cc/proto/layer_position_constraint.proto
diff --git a/cc/proto/layer_position_constraint.proto b/cc/proto/layer_position_constraint.proto
deleted file mode 100644
index f84ebf08526a91774fd6c16ea244e1ac50b6858d..0000000000000000000000000000000000000000
--- a/cc/proto/layer_position_constraint.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";
-
-option optimize_for = LITE_RUNTIME;
-
-package cc.proto;
-
-message LayerPositionConstraint {
-  optional bool is_fixed_position = 1;
-  optional bool is_fixed_to_right_edge = 2;
-  optional bool is_fixed_to_bottom_edge = 3;
-};