Removing #ifdefs for WEB_AUDIO compile time flag.

Source/build/features.gypi

Index: Source/build/features.gypi
diff --git a/Source/build/features.gypi b/Source/build/features.gypi
index 237be2273d2257d40734c705171fa2bff04604db..ce8da5348d962391a01b2402b90bd5939d65f503 100644
--- a/Source/build/features.gypi
+++ b/Source/build/features.gypi
@@ -54,7 +54,6 @@
       ['OS!="android"', {
         'feature_defines': [
           'ENABLE_INPUT_MULTIPLE_FIELDS_UI=1',
-          'ENABLE_WEB_AUDIO=1'
         ],
       }],
       # Mac OS X uses Accelerate.framework FFT by default instead of FFmpeg.
@@ -68,7 +67,6 @@
           'WTF_USE_WEBAUDIO_OPENMAX_DL_FFT=1',
           # Enabling the FFT is enough to enable WebAudio support to
           # allow most WebAudio features to work on Android.
-          'ENABLE_WEB_AUDIO=1',

[Mike West, 2014/09/25 13:40:04]

Given the comments here, it's not at all clear that we can remove this
compile-time flag. kbr@, WDYT?

[Raymond Toy, 2014/09/25 17:43:18]

The comments should probably be updated.

I have personally tested webaudio on Android arm, arm64, x86, and mips. These
all build and run as expected. (I have not tested x86 or mips recently,
however.)

         ],
       }],
       # Mac OS X has not implemented support for ENABLE(OPENTYPE_VERTICAL) yet