webm2pes: Begin addition of tests.

Just the basics:
- Some new test utilities.
- Basic setup for webm2pes testing.

Change-Id: I16bf0f5ef36e7c01f2788b2c92600d6a936bbd40

webm2pes.h

@@ -195,6 +195,9 @@ class Webm2Pes {
   // Input timecode scale.
   std::int64_t timecode_scale_ = 1000000;
 };
+
+
+
 }  // namespace libwebm
 
 #endif  // LIBWEBM_WEBM2PES_H_