Fix compilation of components_unittests with disable_file_support=true.

The test components/update_client/crx_downloader_unittest.cc depends
on net::LocalHostTestURLRequestInterceptor class that is not compiled
when disable_file_support is set to true.

Add a new file src/net/features.gni to allow conditional compilation
based on that flag from outside of //net.

BUG=640686

Review-Url: https://codereview.chromium.org/2318343003
Cr-Commit-Position: refs/heads/master@{#417287}

components/update_client/BUILD.gn

@@ -2,6 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//net/features.gni")
+
 static_library("update_client") {
   sources = [
     "action.cc",
@@ -115,7 +117,6 @@ source_set("unit_tests") {
   testonly = true
   sources = [
     "component_patcher_unittest.cc",
-    "crx_downloader_unittest.cc",
     "persisted_data_unittest.cc",
     "ping_manager_unittest.cc",
     "request_sender_unittest.cc",
@@ -126,6 +127,10 @@ source_set("unit_tests") {
     "utils_unittest.cc",
   ]
 
+  if (!disable_file_support) {
+    sources += [ "crx_downloader_unittest.cc" ]
+  }
+
   deps = [
     ":test_support",
     ":unit_tests_bundle_data",

net/BUILD.gn

@@ -8,6 +8,7 @@ import("//build/config/compiler/compiler.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//net/features.gni")
 import("//testing/libfuzzer/fuzzer_test.gni")
 import("//testing/test.gni")
 import("//third_party/icu/config.gni")
@@ -39,24 +40,6 @@ posix_avoid_mmap = is_android && current_cpu != "x86"
 use_v8_in_net = !is_ios
 enable_built_in_dns = !is_ios
 
-declare_args() {
-  # Disables support for file URLs.  File URL support requires use of icu.
-  disable_file_support = false
-
-  # WebSockets and socket stream code are not used on iOS and are optional in
-  # cronet.
-  enable_websockets = !is_ios
-  disable_ftp_support = is_ios || is_chromecast
-
-  # Enable Kerberos authentication. It is disabled by default on ChromeOS, iOS,
-  # Chromecast, at least for now. This feature needs configuration (krb5.conf
-  # and so on).
-  use_kerberos = !is_chromeos && !is_ios && !is_chromecast
-
-  # Do not disable brotli filter by default.
-  disable_brotli_filter = false
-}
-
 config("net_config") {
   defines = []
   if (posix_avoid_mmap) {

net/features.gni

@@ -0,0 +1,23 @@
+# Copyright 2016 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/config/features.gni")
+
+declare_args() {
+  # Disables support for file URLs.  File URL support requires use of icu.
+  disable_file_support = false
+
+  # WebSockets and socket stream code are not used on iOS and are optional in
+  # cronet.
+  enable_websockets = !is_ios
+  disable_ftp_support = is_ios || is_chromecast
+
+  # Enable Kerberos authentication. It is disabled by default on ChromeOS, iOS,
+  # Chromecast, at least for now. This feature needs configuration (krb5.conf
+  # and so on).
+  use_kerberos = !is_chromeos && !is_ios && !is_chromecast
+
+  # Do not disable brotli filter by default.
+  disable_brotli_filter = false
+}