Port two warning flags from gyp to gn.

BUILD.gn

 # Copyright 2014 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("//third_party/icu/config.gni")
 
 # Meta target that includes both icuuc and icui18n. Most targets want both.
 # You can depend on the individually if you need to.
 group("icu") {
   deps = [
@@ skipping 54 matching lines @@
       "-Wno-unused-function",
     ]
   }
   if (is_clang) {
     cflags += [
       "-Wno-deprecated-declarations",
       "-Wno-logical-op-parentheses",
       "-Wno-tautological-compare",
       "-Wno-switch",
     ]
+    if (is_win) {
+      cflags += [
+        # See http://bugs.icu-project.org/trac/ticket/11122
+        '-Wno-inline-new-delete',
+        '-Wno-implicit-exception-spec-mismatch',
+      ]
+    }
   }
 }
 
 component("icui18n") {
   sources = [
     "source/i18n/alphaindex.cpp",
     "source/i18n/anytrans.cpp",
     "source/i18n/astro.cpp",
     "source/i18n/basictz.cpp",
     "source/i18n/bocsu.cpp",
@@ skipping 463 matching lines @@
         sources = [
           "android/icudtl_dat.S",
         ]
       } else {
         assert(false, "No icu data for this platform")
       }
       defines = [ "U_HIDE_DATA_SYMBOL" ]
     }
   }
 }