Motown: Rename Ratio and LinearFunction classes

mojo/services/media/common/cpp/timeline_function.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <limits>
+#include <utility>
+
+#include "mojo/public/cpp/environment/logging.h"
+#include "mojo/services/media/common/cpp/timeline_function.h"
+
+namespace mojo {
+namespace media {
+
+// static
+int64_t TimelineFunction::Apply(
+    int64_t reference_time,
+    int64_t subject_time,
+    const TimelineRate& rate,  // subject_delta / reference_delta
+    int64_t reference_input) {
+  return rate.Scale(reference_input - reference_time) + subject_time;
+}
+
+// static
+TimelineFunction TimelineFunction::Compose(const TimelineFunction& bc,
+                                           const TimelineFunction& ab,
+                                           bool exact) {
+  return TimelineFunction(ab.reference_time(), bc.Apply(ab.subject_time()),
+                          TimelineRate::Product(ab.rate(), bc.rate(), exact));
+}
+
+}  // namespace media
+}  // namespace mojo