Add GN conversions for more GYP flags

build/config/BUILDCONFIG.gn

 # Copyright (c) 2013 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.
 
 # =============================================================================
 # BUILD FLAGS
 # =============================================================================
 #
 # This block lists input arguments to the build, along with their default
 # values. GN requires listing them explicitly so it can validate input and have
@@ skipping 47 matching lines @@
 
   # Selects the desired build flavor. Official builds get additional
   # processing to prepare for release. Normally you will want to develop and
   # test with this flag off.
   is_official_build = false
 
   # Select the desired branding flavor. False means normal Chromium branding,
   # true means official Google Chrome branding (requires extra Google-internal
   # resources).
   is_chrome_branded = false
+
+  # Compile for Address Sanitizer to find memory bugs.
+  is_asan = false
+
+  # Compile for Leak Sanitizer to find leaks.
+  is_lsan = false
+
+  # Compile for Memory Sanitizer to find uninitialized reads.
+  is_msan = false
+
+  # Compile for Thread Sanitizer to find threading bugs.
+  is_tsan = false
 }
 
 # =============================================================================
 # OS DEFINITIONS
 # =============================================================================
 #
 # We set these various is_FOO booleans for convenience in writing OS-based
 # conditions.
 #
 # - is_android, is_chromeos, is_ios, and is_win should be obvious.
@@ skipping 195 matching lines @@
 # =============================================================================
 # BUILD OPTIONS
 # =============================================================================
 
 if (is_component_build) {
   component_mode = "shared_library"
 } else {
   component_mode = "static_library"
 }
 
+# These Sanitizers all imply using the Clang compiler. On Windows they either
+# don't work or work differently.
+if (!is_clang && (is_asan || is_lsan || is_tsan || is_msan)) {
+  is_clang = true
+}
+
 toolkit_uses_gtk = is_linux
 
 # =============================================================================
 # TARGET DEFAULTS
 # =============================================================================
 #
 # Set up the default configuration for every build target of the given type.
 # The values configured here will be automatically set on the scope of the
 # corresponding target. Target definitions can add or remove to the settings
 # here as needed.
@@ skipping 122 matching lines @@
     host_toolchain = "//build/toolchain/linux:64"
   }
 
   if (build_cpu_arch == "arm") {
     set_default_toolchain("//build/toolchain/linux:arm")
   } else if (build_cpu_arch == "x86") {
     set_default_toolchain("//build/toolchain/linux:32")
   } else if (build_cpu_arch == "x64") {
     set_default_toolchain("//build/toolchain/linux:64")
   }
-} else if (is_mac) {
+} else if (is_mac || is_ios) {
   host_toolchain = "//build/toolchain/mac:clang"
   set_default_toolchain(host_toolchain)
 }