[android] Add toolchain path logic to gyp config.

build/android.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 15 matching lines @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 # Definitions for building standalone V8 binaries to run on Android.
 # This is mostly excerpted from:
 # http://src.chromium.org/viewvc/chrome/trunk/src/build/common.gypi
 
 {
   'variables': {
     # Location of Android NDK.
     'variables': {
-      'android_ndk_root%': '<!(/bin/echo -n $ANDROID_NDK_ROOT)',
-      'android_toolchain%': '<!(/bin/echo -n $ANDROID_TOOLCHAIN)',
+      'variables': {
+        # The Android toolchain needs to use the absolute path to the NDK
+        # because it is used at different levels in the GYP files.
+        'android_ndk_root%': '<!(cd <(DEPTH) && pwd -P)/third_party/android_tools/ndk/',
+        'android_host_arch%': "<!(uname -m | sed -e 's/i[3456]86/x86/')",
+        'host_os%': "<!(uname -s | sed -e 's/Linux/linux/;s/Darwin/mac/')",
+      },
+
+      # Copy conditionally-set variables out one scope.
+      'android_ndk_root%': '<(android_ndk_root)',
+
+      # Android API level 16 is JB (Android 4.1) which is the minimum

[ulan, 2015/06/22 10:41:25]

Update the comment?

[Michael Achenbach, 2015/06/22 11:29:46]

Removing the comment.

+      # platform requirement for Chrome on Android, we use it for native
+      # code compilation.
+      'conditions': [
+        ['target_arch == "ia32"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/x86-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+        ['target_arch == "x64"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/x86_64-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+        ['target_arch=="arm"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/arm-linux-androideabi-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+        ['target_arch == "arm64"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/aarch64-linux-android-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+        ['target_arch == "mipsel"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/mipsel-linux-android-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+        ['target_arch == "mips64el"', {
+          'android_toolchain%': '<(android_ndk_root)/toolchains/mips64el-linux-android-4.9/prebuilt/<(host_os)-<(android_host_arch)/bin',
+        }],
+      ],
     },
+
     'conditions': [
       ['android_ndk_root==""', {
         'variables': {
           'android_sysroot': '<(android_toolchain)/sysroot/',
           'android_stlport': '<(android_toolchain)/sources/cxx-stl/stlport/',
         },
         'android_include': '<(android_sysroot)/usr/include',
         'conditions': [
           ['target_arch=="x64"', {
             'android_lib': '<(android_sysroot)/usr/lib64',
@@ skipping 208 matching lines @@
         'ldflags!': [
           '-Wl,-z,noexecstack',
           '-Wl,--gc-sections',
           '-Wl,-O1',
           '-Wl,--as-needed',
         ],
       }],
     ],  # target_conditions
   },  # target_defaults
 }