Added some missing includes, removed one include and removed an undef.

content/renderer/pepper/pepper_media_stream_video_track_host.cc

Index: content/renderer/pepper/pepper_media_stream_video_track_host.cc
diff --git a/content/renderer/pepper/pepper_media_stream_video_track_host.cc b/content/renderer/pepper/pepper_media_stream_video_track_host.cc
index af1790e6ce941bfe6009a100fbd7e9956fb2b186..2e7e2c2363c87d2ab0c916eeeb152ad4ee08de2a 100644
--- a/content/renderer/pepper/pepper_media_stream_video_track_host.cc
+++ b/content/renderer/pepper/pepper_media_stream_video_track_host.cc
@@ -18,11 +18,6 @@
 #include "ppapi/host/host_message_context.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/shared_impl/media_stream_buffer.h"
-
-// IS_ALIGNED is also defined in
-// third_party/webrtc/overrides/webrtc/base/basictypes.h
-// TODO(ronghuawu): Avoid undef.
-#undef IS_ALIGNED
 #include "third_party/libyuv/include/libyuv.h"
 
 using media::VideoFrame;