From 36c5b170e722362d4b5f7cb6e4e0099ed227a307 Mon Sep 17 00:00:00 2001
From: Miklos Vajna <vmiklos@collabora.co.uk>
Date: Thu, 13 Apr 2017 10:09:06 +0200
Subject: core: allow building against system zlib

In a way similar to the existing USE_SYSTEM_LIBJPEG. The default is of
course still the DEPS-based zlib checkout.

Change-Id: I649e75beb1a19c4cf7abda42fa10ebe5babfe946
Reviewed-on: https://pdfium-review.googlesource.com/4070
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
---
 AUTHORS                               |  1 +
 BUILD.gn                              |  2 +-
 core/fxcodec/codec/fx_codec_flate.cpp |  5 +++++
 skia/BUILD.gn                         |  2 +-
 third_party/BUILD.gn                  | 21 +++++++++++++++++++--
 5 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 6c2a295990..7499c1094c 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -36,6 +36,7 @@ Robert Sesek <rsesek@chromium.org>
 Sam Clegg <sbc@chromium.org>
 Thomas Sepez <tsepez@chromium.org>
 
+Collabora Ltd. <*@collabora.co.uk>
 DocsCorp Pty Ltd. <*@docscorp.com>
 Foxit Software Inc <*@foxitsoftware.com>
 Google Inc. <*@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index 1d8f3530ec..77bdeb5e77 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -703,7 +703,7 @@ static_library("fxcodec") {
     "third_party:fx_lcms2",
     "third_party:fx_libopenjpeg",
     "//third_party:jpeg",
-    "//third_party/zlib:zlib",
+    "//third_party:zlib",
   ]
 
   if (pdf_enable_xfa) {
diff --git a/core/fxcodec/codec/fx_codec_flate.cpp b/core/fxcodec/codec/fx_codec_flate.cpp
index ef78248217..3747b20cc3 100644
--- a/core/fxcodec/codec/fx_codec_flate.cpp
+++ b/core/fxcodec/codec/fx_codec_flate.cpp
@@ -15,7 +15,12 @@
 #include "core/fxcrt/fx_ext.h"
 #include "third_party/base/numerics/safe_conversions.h"
 #include "third_party/base/ptr_util.h"
+
+#if defined(USE_SYSTEM_ZLIB)
+#include <zlib.h>
+#else
 #include "third_party/zlib/zlib.h"
+#endif
 
 extern "C" {
 
diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index 31a851d576..a129ef9d59 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -317,7 +317,7 @@ component("skia") {
   deps = [
     ":skia_opts",
     "//:freetype_common",
-    "//third_party/zlib:zlib",
+    "//third_party:zlib",
   ]
 
   if (is_linux) {
diff --git a/third_party/BUILD.gn b/third_party/BUILD.gn
index c270a1063a..17c9c22832 100644
--- a/third_party/BUILD.gn
+++ b/third_party/BUILD.gn
@@ -288,6 +288,8 @@ if (!build_with_chromium) {
     # Uses libjpeg_turbo as the jpeg implementation. Has no effect if
     # use_system_libjpeg is set.
     use_libjpeg_turbo = true
+
+    use_system_zlib = false
   }
 
   config("system_libjpeg_config") {
@@ -316,6 +318,21 @@ if (!build_with_chromium) {
       ]
     }
   }
+
+  config("system_zlib_config") {
+    libs = [ "z" ]
+    defines = [ "USE_SYSTEM_ZLIB" ]
+  }
+
+  group("zlib") {
+    if (use_system_zlib) {
+      public_configs = [ ":system_zlib_config" ]
+    } else {
+      public_deps = [
+        "//third_party/zlib",
+      ]
+    }
+  }
 }
 
 config("fx_libopenjpeg_warnings") {
@@ -395,7 +412,7 @@ static_library("fx_lpng") {
   defines = []
   cflags = []
   deps = [
-    "//third_party/zlib",
+    "//third_party:zlib",
   ]
 
   if (current_cpu == "x86" || current_cpu == "x64") {
@@ -435,7 +452,7 @@ if (pdf_enable_xfa) {
     }
     deps = [
       "//third_party:jpeg",
-      "//third_party/zlib",
+      "//third_party:zlib",
     ]
     sources = [
       "libtiff/tif_aux.c",
-- 
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