Enable WebAudio by default for Android/x86.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index c9d55f1c85044e3b93069949088b5bdb3f3f19a6..99128b159bb46afade5da0c72ee1e83cae59d66d 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1786,11 +1786,6 @@
       ['use_titlecase_in_grd_files==1', {
         'grit_defines': ['-D', 'use_titlecase'],
       }],
-      ['OS=="android" and (target_arch=="ia32" or target_arch=="x64")', {
-        # WebAudio on Android/x86 is disabled by default, unlike
-        # everywhere else, so use appropriate message.
-        'grit_defines': ['-D', 'use_webaudio_enable_message'],
-      }],
       ['use_third_party_translations==1', {
         'grit_defines': ['-D', 'use_third_party_translations'],
         'locales': [