Add MIPS SIMD Arch (MSA) build flags for GYP/GN builds

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/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 550 matching lines @@
             "-mips32r6",
             "-Wa,-mips32r6",
           ]
           if (is_android) {
             ldflags += [
               "-mips32r6",
               "-Wl,-melf32ltsmip",
             ]
           }
         }
+        if (mips_use_msa == true) {
+          cflags += [
+            "-mmsa",
+            "-mfp64",
+            "-msched-weight",
+            "-mload-store-pairs",
+          ]
+        }
       } else if (mips_arch_variant == "r2") {
         if (is_clang) {
           if (is_android) {
             cflags += [
               "--target=mipsel-linux-android",
               "-march=mipsel",
               "-mcpu=mips32r2",
             ]
             ldflags += [ "--target=mipsel-linux-android" ]
           } else {
@@ skipping 56 matching lines @@
             ]
             ldflags += [ "--target=mips64el-linux-android" ]
           }
         } else {
           cflags += [
             "-mips64r6",
             "-Wa,-mips64r6",
           ]
           ldflags += [ "-mips64r6" ]
         }
+        if (mips_use_msa == true) {
+          cflags += [
+            "-mmsa",
+            "-mfp64",
+            "-msched-weight",
+            "-mload-store-pairs",
+          ]
+        }
       } else if (mips_arch_variant == "r2") {
         cflags += [
           "-mips64r2",
           "-Wa,-mips64r2",
         ]
         ldflags += [ "-mips64r2" ]
       }
     } else if (current_cpu == "pnacl" && is_nacl_nonsfi) {
       if (target_cpu == "x86" || target_cpu == "x64") {
         cflags += [
@@ skipping 909 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
   }
 }