Fix official builds on ios 8.3+

build/config/compiler/BUILD.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.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
 import("//build_overrides/build.gni")
 
 if (current_cpu == "arm" || current_cpu == "arm64") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
   import("//build/config/mips.gni")
 }
 if (is_mac) {
   import("//build/config/mac/symbols.gni")
 }
+if (is_ios) {
+  import("//build/config/ios/ios_sdk.gni")
+}
 
 declare_args() {
   # Default to warnings as errors for default workflow, where we catch
   # warnings with known toolchains. Allow overriding this e.g. for Chromium
   # builds on Linux that could use a different version of the compiler.
   # With GCC, warnings in no-Chromium code are always not treated as errors.
   treat_warnings_as_errors = true
 
   # Normally, Android builds are lightly optimized, even for debug builds, to
   # keep binary size down. Setting this flag to true disables such optimization
@@ skipping 1062 matching lines @@
 
         # TODO(hans): https://crbug.com/637306
         "-Wno-address-of-packed-member",
 
         # TODO(hans): https://crbug.com/681136
         "-Wno-unused-lambda-capture",
 
         # TODO(thakis ): https://crbug.com/683349
         "-Wno-user-defined-warnings",
       ]
+    } else if (use_xcode_clang &&
+               (xcode_version == "0830" || xcode_version == "0831" ||
+                xcode_version == "0832")) {
+      # This is necessary to allow a progressive transition from using xcode 8 to 8.3. Remove when all bots are migrated to 8.3.
+      cflags += [
+        # TODO(thakis): https://crbug.com/604888
+        "-Wno-undefined-var-template",
+
+        # TODO(hans): https://crbug.com/637306
+        "-Wno-address-of-packed-member",
+      ]
     }
   }
 }
 
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)
 # part of Chromium.
 
 config("chromium_code") {
@@ skipping 607 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }