Add support for building v8 on mips and mips64 using GN.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index f129035e796bb80e037ce33e88c7ace0495fe2cc..792b47c2a8750e44470a4eff5eed88c2257401e9 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -13,7 +13,8 @@ import("//build_overrides/build.gni")
 if (current_cpu == "arm" || current_cpu == "arm64") {
   import("//build/config/arm.gni")
 }
-if (current_cpu == "mipsel" || current_cpu == "mips64el") {
+if (current_cpu == "mipsel" || current_cpu == "mips64el" ||
+    current_cpu == "mips" || current_cpu == "mips64") {
   import("//build/config/mips.gni")
 }
 if (is_mac) {
@@ -700,6 +701,40 @@ config("compiler_cpu_abi") {
       }
 
       cflags += [ "-m${mips_float_abi}-float" ]
+    } else if (current_cpu == "mips" && !is_nacl) {
+      if (mips_arch_variant == "r6") {
+        cflags += [
+          "-mips32r6",
+          "-Wa,-mips32r6",
+        ]
+        if (mips_use_msa == true) {
+          cflags += [
+            "-mmsa",
+            "-mfp64",
+          ]
+        }
+      } else if (mips_arch_variant == "r2") {
+        cflags += [
+          "-mips32r2",
+          "-Wa,-mips32r2",
+        ]
+        if (mips_float_abi == "hard" && mips_fpu_mode != "") {
+          cflags += [ "-m$mips_fpu_mode" ]
+        }
+      } else if (mips_arch_variant == "r1") {
+        cflags += [
+          "-mips32",
+          "-Wa,-mips32",
+        ]
+      }
+
+      if (mips_dsp_rev == 1) {
+        cflags += [ "-mdsp" ]
+      } else if (mips_dsp_rev == 2) {
+        cflags += [ "-mdspr2" ]
+      }
+
+      cflags += [ "-m${mips_float_abi}-float" ]
     } else if (current_cpu == "mips64el") {
       if (mips_arch_variant == "r6") {
         if (is_clang) {
@@ -731,6 +766,26 @@ config("compiler_cpu_abi") {
         ]
         ldflags += [ "-mips64r2" ]
       }
+    } else if (current_cpu == "mips64") {
+      if (mips_arch_variant == "r6") {
+        cflags += [
+          "-mips64r6",
+          "-Wa,-mips64r6",
+        ]
+        ldflags += [ "-mips64r6" ]
+        if (mips_use_msa == true) {
+          cflags += [
+            "-mmsa",
+            "-mfp64",
+          ]
+        }
+      } 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 += [
@@ -1179,7 +1234,8 @@ config("chromium_code") {
     if (!is_debug && !using_sanitizer &&
         (!is_linux || !is_clang || is_official_build) &&
         current_cpu != "s390x" && current_cpu != "s390" &&
-        current_cpu != "ppc64" && current_cpu != "ppc64") {
+        current_cpu != "ppc64" && current_cpu != "ppc64" &&
+        current_cpu != "mips" && current_cpu != "mips64") {
       # _FORTIFY_SOURCE isn't really supported by Clang now, see
       # http://llvm.org/bugs/show_bug.cgi?id=16821.
       # It seems to work fine with Ubuntu 12 headers though, so use it in