Unbundle Linux system libraries for GN

Adds unbundling on linux for the zlib, minizip, libpng, libwebp,
libevent, libxml, libxslt and snappy libraries.

Change-Id: I7bc8f418669a9908f0c1bc9393771e233f9f491a
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

9 files changed, 220 insertions, 27 deletions

diff --git a/chromium/base/third_party/libevent/BUILD.gn b/chromium/base/third_party/libevent/BUILD.gn
index e934454a10f..625dfea3b81 100644
--- a/chromium/base/third_party/libevent/BUILD.gn
+++ b/chromium/base/third_party/libevent/BUILD.gn
@@ -3,8 +3,13 @@
 # found in the LICENSE file.
 
 import("//build/config/nacl/config.gni")
+import("//build/shim_headers.gni")
 
-static_library("libevent") {
+declare_args() {
+  use_system_libevent = false
+}
+
+static_library("bundled_libevent") {
   sources = [
     "buffer.c",
     "evbuffer.c",
@@ -78,3 +83,23 @@ static_library("libevent") {
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 }
+
+shim_headers("libevent_shim") {
+  root_path = "."
+  headers = [ "event.h" ]
+}
+
+source_set("system_libevent") {
+  deps = [
+    ":libevent_shim",
+  ]
+  libs = [ "event" ]
+}
+
+group("libevent") {
+  if (use_system_libevent) {
+    public_deps = [ ":system_libevent" ]
+  } else {
+    public_deps = [ ":bundled_libevent" ]
+  }
+}
diff --git a/chromium/build/config/compiler/BUILD.gn b/chromium/build/config/compiler/BUILD.gn
index d249b842128..2d2db0078d8 100644
--- a/chromium/build/config/compiler/BUILD.gn
+++ b/chromium/build/config/compiler/BUILD.gn
@@ -131,8 +131,8 @@ if (use_debug_fission == "default") {
 # this and specify their own include paths.
 config("default_include_dirs") {
   include_dirs = [
-    "//",
     root_gen_dir,
+    "//",
   ]
 }
 
diff --git a/chromium/build/shim_headers.gni b/chromium/build/shim_headers.gni
index a37bd4a1d8d..88f795b4160 100644
--- a/chromium/build/shim_headers.gni
+++ b/chromium/build/shim_headers.gni
@@ -5,7 +5,7 @@
 template("shim_headers") {
   action_name = "gen_${target_name}"
   config_name = "${target_name}_config"
-  shim_headers_path = "${root_gen_dir}/shim_headers/${target_name}"
+  shim_headers_path = "${root_gen_dir}"
 
   config(config_name) {
     include_dirs = [ shim_headers_path ]
diff --git a/chromium/third_party/libpng/BUILD.gn b/chromium/third_party/libpng/BUILD.gn
index 88a28cfaec2..b53bd668c54 100644
--- a/chromium/third_party/libpng/BUILD.gn
+++ b/chromium/third_party/libpng/BUILD.gn
@@ -5,6 +5,10 @@
 import("//build/config/chromecast_build.gni")
 import("//build/config/arm.gni")
 
+declare_args() {
+  use_system_libpng = false
+}
+
 config("libpng_config") {
   include_dirs = [ "." ]
 
@@ -101,16 +105,35 @@ source_set("libpng_sources") {
   configs += [ ":clang_warnings" ]
 }
 
-if (is_win) {
-  component("libpng") {
-    public_deps = [
-      ":libpng_sources",
-    ]
+if (!use_system_libpng) {
+  if (is_win) {
+    component("libpng") {
+      public_deps = [
+        ":libpng_sources",
+      ]
+    }
+  } else {
+    group("libpng") {
+      public_deps = [
+        ":libpng_sources",
+      ]
+    }
   }
 } else {
-  group("libpng") {
-    public_deps = [
-      ":libpng_sources",
+  import("//build/config/linux/pkg_config.gni")
+  import("//build/shim_headers.gni")
+  pkg_config("system_libpng") {
+    packages = [ "libpng" ]
+  }
+  shim_headers("libpng_shim") {
+    root_path = "."
+    headers = [
+      "png.h",
+      "pngconf.h",
     ]
   }
+  source_set("libpng") {
+    deps = [ ":libpng_shim" ]
+    public_configs = [ ":system_libpng" ]
+  }
 }
diff --git a/chromium/third_party/libwebp/BUILD.gn b/chromium/third_party/libwebp/BUILD.gn
index 470bd2926c6..e478d3a206c 100644
--- a/chromium/third_party/libwebp/BUILD.gn
+++ b/chromium/third_party/libwebp/BUILD.gn
@@ -4,6 +4,11 @@
 
 import("//build/config/arm.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/config/linux/pkg_config.gni")
+
+declare_args() {
+  use_system_libwebp = false
+}
 
 config("libwebp_config") {
   include_dirs = [ "." ]
@@ -290,16 +295,27 @@ static_library("libwebp_utils") {
   public_configs = [ ":libwebp_utils_warnings" ]
 }
 
-group("libwebp") {
-  deps = [
-    ":libwebp_dec",
-    ":libwebp_demux",
-    ":libwebp_dsp",
-    ":libwebp_enc",
-    ":libwebp_utils",
-  ]
-  public_configs = [ ":libwebp_config" ]
-  if (use_dsp_neon) {
-    deps += [ ":libwebp_dsp_neon" ]
+if (!use_system_libwebp) {
+  group("libwebp") {
+    deps = [
+      ":libwebp_dec",
+      ":libwebp_demux",
+      ":libwebp_dsp",
+      ":libwebp_enc",
+      ":libwebp_utils",
+    ]
+    public_configs = [ ":libwebp_config" ]
+    if (use_dsp_neon) {
+      deps += [ ":libwebp_dsp_neon" ]
+    }
+  }
+}
+
+if (use_system_libwebp) {
+  pkg_config("system_libwebp") {
+    packages = [ "libwebp", "libwebpdemux" ]
+  }
+  group("libwebp") {
+    public_configs = [ ":system_libwebp" ]
   }
 }
diff --git a/chromium/third_party/libxml/BUILD.gn b/chromium/third_party/libxml/BUILD.gn
index 70b66ab53b3..383157ca896 100644
--- a/chromium/third_party/libxml/BUILD.gn
+++ b/chromium/third_party/libxml/BUILD.gn
@@ -12,6 +12,10 @@ if (is_linux || is_android || is_nacl) {
   os_include = "win32"
 }
 
+declare_args() {
+  use_system_libxml = false
+}
+
 config("libxml_config") {
   # Define LIBXML_STATIC as nothing to match how libxml.h (an internal header)
   # defines LIBXML_STATIC, otherwise we get the macro redefined warning from
@@ -63,7 +67,7 @@ config("libxml_warnings") {
   }
 }
 
-static_library("libxml") {
+static_library("bundled_libxml") {
   output_name = "libxml2"
   sources = [
     "chromium/libxml_utils.cc",
@@ -208,3 +212,22 @@ static_library("libxml") {
 
   include_dirs = [ "$os_include" ]
 }
+
+if (use_system_libxml) {
+  import("//build/config/linux/pkg_config.gni")
+  pkg_config("system_libxml") {
+    packages = [ "libxml-2.0" ]
+  }
+  source_set("libxml") {
+    sources = [
+      "chromium/libxml_utils.cc",
+      "chromium/libxml_utils.h",
+    ]
+
+    public_configs = [ ":system_libxml" ]
+  }
+} else {
+  group("libxml") {
+    public_deps = [ ":bundled_libxml" ]
+  }
+}
diff --git a/chromium/third_party/libxslt/BUILD.gn b/chromium/third_party/libxslt/BUILD.gn
index 6e8dcc980a2..7678d7f0c44 100644
--- a/chromium/third_party/libxslt/BUILD.gn
+++ b/chromium/third_party/libxslt/BUILD.gn
@@ -2,6 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+declare_args() {
+  use_system_libxslt = false
+}
+
 config("libxslt_config") {
   defines = [ "LIBXSLT_STATIC" ]
   include_dirs = [ "." ]
@@ -20,7 +24,7 @@ config("libxslt_warnings") {
   }
 }
 
-static_library("libxslt") {
+static_library("bundled_libxslt") {
   sources = [
     "libxslt/attributes.c",
     "libxslt/attributes.h",
@@ -101,3 +105,17 @@ static_library("libxslt") {
     "//third_party/libxml",
   ]
 }
+
+if (use_system_libxslt) {
+  import("//build/config/linux/pkg_config.gni")
+  pkg_config("system_libxslt") {
+    packages = [ "libxslt" ]
+  }
+  source_set("libxslt") {
+    public_configs = [ ":system_libxslt" ]
+  }
+} else {
+  group("libxslt") {
+    public_deps = [ ":bundled_libxslt" ]
+  }
+}
diff --git a/chromium/third_party/snappy/BUILD.gn b/chromium/third_party/snappy/BUILD.gn
index 7eabb7b19e9..821ed297f90 100644
--- a/chromium/third_party/snappy/BUILD.gn
+++ b/chromium/third_party/snappy/BUILD.gn
@@ -2,6 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+declare_args() {
+  use_system_snappy = false
+}
+
 config("snappy_config") {
   include_dirs = [ "src" ]
 
@@ -24,7 +28,7 @@ config("snappy_warnings") {
   }
 }
 
-static_library("snappy") {
+static_library("bundled_snappy") {
   sources = [
     "src/snappy-internal.h",
     "src/snappy-sinksource.cc",
@@ -54,3 +58,28 @@ static_library("snappy") {
     configs -= [ "//build/config/clang:extra_warnings" ]
   }
 }
+
+if (use_system_snappy) {
+  import("//build/shim_headers.gni")
+
+  shim_headers("snappy_shim") {
+    root_path = "src"
+    headers = [
+      "snappy-c.h",
+      "snappy-sinksource.h",
+      "snappy-stubs-public.h",
+      "snappy.h",
+    ]
+  }
+
+  source_set("snappy") {
+    deps = [
+      ":snappy_shim",
+    ]
+    libs = [ "snappy" ]
+  }
+} else {
+  group("snappy") {
+    public_deps = [ ":bundled_snappy" ]
+  }
+}
diff --git a/chromium/third_party/zlib/BUILD.gn b/chromium/third_party/zlib/BUILD.gn
index 5086563cf55..ff7462ba1f5 100644
--- a/chromium/third_party/zlib/BUILD.gn
+++ b/chromium/third_party/zlib/BUILD.gn
@@ -2,6 +2,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/shim_headers.gni")
+
+declare_args() {
+  use_system_zlib = false
+  use_system_minizip = false
+}
+
 config("zlib_config") {
   include_dirs = [ "." ]
 }
@@ -34,7 +41,7 @@ config("zlib_warnings") {
   }
 }
 
-static_library("zlib") {
+static_library("bundled_zlib") {
   if (!is_win) {
     # Don't stomp on "libzlib" on other platforms.
     output_name = "chrome_zlib"
@@ -89,6 +96,31 @@ static_library("zlib") {
   ]
 }
 
+shim_headers("zlib_shim") {
+  root_path = "."
+  headers = [ "zlib.h" ]
+}
+
+config("use_system_zlib") {
+  defines = [ "USE_SYSTEM_ZLIB=1" ]
+}
+
+source_set("system_zlib") {
+  deps = [
+    ":zlib_shim",
+  ]
+  libs = [ "z" ]
+  public_configs = [ ":use_system_zlib" ]
+}
+
+group("zlib") {
+  if (use_system_zlib) {
+    public_deps = [ ":system_zlib" ]
+  } else {
+    public_deps = [ ":bundled_zlib" ]
+  }
+}
+
 config("minizip_warnings") {
   visibility = [ ":*" ]
   if (is_clang) {
@@ -97,7 +129,7 @@ config("minizip_warnings") {
   }
 }
 
-static_library("minizip") {
+static_library("bundled_minizip") {
   sources = [
     "contrib/minizip/ioapi.c",
     "contrib/minizip/ioapi.h",
@@ -135,6 +167,33 @@ static_library("minizip") {
   public_configs = [ ":zlib_config" ]
 }
 
+shim_headers("minizip_shim") {
+  root_path = "contrib"
+  headers = [
+    "minizip/crypt.h",
+    "minizip/ioapi.h",
+    "minizip/iowin32.h",
+    "minizip/mztools.h",
+    "minizip/unzip.h",
+    "minizip/zip.h",
+  ]
+}
+
+source_set("system_minizip") {
+  deps = [
+    ":minizip_shim",
+  ]
+  libs = [ "minizip" ]
+}
+
+group("minizip") {
+  if (use_system_minizip) {
+    public_deps = [ ":system_minizip" ]
+  } else {
+    public_deps = [ ":bundled_minizip" ]
+  }
+}
+
 static_library("zip") {
   sources = [
     "google/zip.cc",