webm2pes: Move main() and helper functions into their own files.

- main() and Usage() to webm2pes_main.cc
- Other helpers to common/libwebm_utils.{cc,h}

Change-Id: I59e45f0e63449066b493c4e536e0be001372504c

common/libwebm_utils.h

@@ -0,0 +1,42 @@
+// Copyright (c) 2015 The WebM project authors. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the LICENSE file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS.  All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+#ifndef LIBWEBM_COMMON_LIBWEBM_UTILS_H_
+#define LIBWEBM_COMMON_LIBWEBM_UTILS_H_
+
+#include <cstdio>
+#include <vector>
+
+namespace libwebm {
+
+struct Range {
+  Range(std::size_t off, std::size_t len) : offset(off), length(len) {}
+  Range() = delete;
+  Range(const Range&) = default;
+  Range(Range&&) = default;
+  ~Range() = default;
+  const std::size_t offset;
+  const std::size_t length;
+};
+
+typedef std::vector<Range> Ranges;
+
+// Converts |nanoseconds| to 90000 Hz clock ticks and returns the value.
+std::int64_t NanosecondsTo90KhzTicks(std::int64_t nanoseconds);
+
+// Returns true and stores frame offsets and lengths in |frame_ranges| when
+// |frame| has a valid VP9 super frame index.
+bool ParseVP9SuperFrameIndex(const std::uint8_t* frame,
+                             std::size_t frame_length,
+                             Ranges* frame_ranges);
+
+// Writes |val| to |fileptr| and returns true upon success.
+bool WriteUint8(std::uint8_t val, std::FILE* fileptr);
+
+}  // namespace libwebm
+
+#endif  // LIBWEBM_COMMON_LIBWEBM_UTILS_H_