move zip and compression_utils targets into their own BUILD.gn file

This came up while doing commit 3fe737215d43: ("third_party/zlib: fix
for "gn check""), at https://chromium-review.googlesource.com/508355

zip and compression_utils are libraries built on top of zlib and base,
and they don't really belong to third_party/zlib. As a first move
into pulling them out of third_party, we are extracting their
targets out of zlib's BUILD.gn file.

BUG=None

Change-Id: I927d212b8e68ddef1961e2f1971eee5bcf0a6df7
Reviewed-on: https://chromium-review.googlesource.com/509510


Reviewed-by: Matt Sarett <msarett@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Thiago Farina <tfarina@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#473595}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: d8a8a07cc7b4196d00c7ecb3eeb96671cd189dea

BUILD.gn

@@ -2,8 +2,6 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build_overrides/build.gni")
-
 config("zlib_config") {
   include_dirs = [ "." ]
 }
@@ -136,31 +134,3 @@ static_library("minizip") {
   ]
   public_configs = [ ":zlib_config" ]
 }
-
-if (build_with_chromium) {
-  static_library("zip") {
-    sources = [
-      "google/zip.cc",
-      "google/zip.h",
-      "google/zip_internal.cc",
-      "google/zip_internal.h",
-      "google/zip_reader.cc",
-      "google/zip_reader.h",
-    ]
-    deps = [
-      ":minizip",
-      "//base",
-    ]
-  }
-
-  static_library("compression_utils") {
-    sources = [
-      "google/compression_utils.cc",
-      "google/compression_utils.h",
-    ]
-    deps = [
-      ":zlib",
-      "//base",
-    ]
-  }
-}

google/BUILD.gn

+# Copyright 2017 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.
+
+import("//build_overrides/build.gni")
+
+if (build_with_chromium) {
+  static_library("zip") {
+    sources = [
+      "zip.cc",
+      "zip.h",
+      "zip_internal.cc",
+      "zip_internal.h",
+      "zip_reader.cc",
+      "zip_reader.h",
+    ]
+    deps = [
+      "//base",
+      "//third_party/zlib:minizip",
+    ]
+  }
+
+  static_library("compression_utils") {
+    sources = [
+      "compression_utils.cc",
+      "compression_utils.h",
+    ]
+    deps = [
+      "//base",
+      "//third_party/zlib",
+    ]
+  }
+}