Enable FDO for v8 in android build.

build/toolchain.gypi

 # Copyright 2013 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 603 matching lines @@
             'xcode_settings': {
               'ARCHS': [ 'i386' ],
             },
           }],
           ['_toolset=="target"', {
             'conditions': [
               ['target_cxx_is_biarch==1 and nacl_target_arch!="nacl_x64"', {
                 'cflags': [ '-m32' ],
                 'ldflags': [ '-m32' ],
               }],
+              # Enable feedback-directed optimisation when building in android.
+              [ 'android_webview_build == 1', {
+                'aosp_build_settings': {
+                  'LOCAL_FDO_SUPPORT': 'true',
+                },
+              }],
             ],
             'xcode_settings': {
               'ARCHS': [ 'i386' ],
             },
           }],
         ],
       }],
       ['(OS=="linux" or OS=="android") and \
         (v8_target_arch=="x64" or v8_target_arch=="arm64")', {
         'target_conditions': [
           ['_toolset=="host"', {
             'conditions': [
               ['host_cxx_is_biarch==1', {
                 'cflags': [ '-m64' ],
                 'ldflags': [ '-m64' ]
               }],
              ],
            }],
            ['_toolset=="target"', {
              'conditions': [
                ['target_cxx_is_biarch==1', {
                  'cflags': [ '-m64' ],
                  'ldflags': [ '-m64' ],
                }],
+               # Enable feedback-directed optimisation when building in android.
+               [ 'android_webview_build == 1', {
+                 'aosp_build_settings': {
+                   'LOCAL_FDO_SUPPORT': 'true',
+                 },
+               }],
              ]
            }],
          ],
       }],
       ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris" \
          or OS=="netbsd" or OS=="qnx"', {
         'conditions': [
           [ 'v8_no_strict_aliasing==1', {
             'cflags': [ '-fno-strict-aliasing' ],
           }],
@@ skipping 305 matching lines @@
                 'OptimizeReferences': '2',
                 'EnableCOMDATFolding': '2',
               },
             },
           }],  # OS=="win"
         ],  # conditions
       },  # Release
     },  # configurations
   },  # target_defaults
 }