Bug 1508905 Include WebAudio files forked from Blink in static-analysis review support r=Ehsan

Given the differences already between upstream and this fork, I expect the pros of additional static analysis would out-weigh the cons.

Depends on D12508

Differential Revision: https://phabricator.services.mozilla.com/D12509

--HG--
extra : moz-landing-system : lando

tools/rewriting/ThirdPartyPaths.txt

@@ -16,8 +16,6 @@ dom/media/platforms/ffmpeg/ffmpeg58/
 dom/media/platforms/ffmpeg/libav53/
 dom/media/platforms/ffmpeg/libav54/
 dom/media/platforms/ffmpeg/libav55/
-dom/media/webaudio/FFTBlock.cpp
-dom/media/webaudio/blink/
 dom/media/webspeech/recognition/endpointer.cc
 dom/media/webspeech/recognition/endpointer.h
 dom/media/webspeech/recognition/energy_endpointer.cc