Make PP_TimeTicks actually be a tick counter rather than be the same as the

webkit/plugins/ppapi/time_conversion_unittest.cc

+// Copyright (c) 2011 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 <math.h>
+#include <stdlib.h>
+
+#include "testing/gtest/include/gtest/gtest.h"
+#include "webkit/plugins/ppapi/time_conversion.h"
+
+namespace webkit {
+namespace ppapi {
+
+// Slop we'll allow in two Time "internal values" to consider them equal.
+// Double conversion can introduce rounding errors. The internal values are in
+// microseconds, so an error here is very small.
+static const int kTimeInternalValueSlop = 2;
+
+// Same as above in double-precision seconds units.
+static const double kTimeSecondsSlop =
+    static_cast<double>(kTimeInternalValueSlop) /
+    base::Time::kMicrosecondsPerSecond;
+
+TEST(TimeConversion, Time) {
+  // Should be able to round-trip.
+  base::Time now = base::Time::Now();
+  base::Time converted = PPTimeToTime(TimeToPPTime(now));
+  EXPECT_GE(kTimeInternalValueSlop,
+            abs(static_cast<int>((converted - now).ToInternalValue())));
+
+  // Units should be in seconds.
+  base::Time one_second_from_now = now + base::TimeDelta::FromSeconds(1);
+  EXPECT_EQ(1.0, TimeToPPTime(one_second_from_now) - TimeToPPTime(now));
+}
+
+TEST(TimeConversion, EventTime) {
+  // Should be able to round-trip.
+  base::Time now = base::Time::Now();
+  double event_now = now.ToDoubleT();
+  double converted = EventTimeToPPTimeTicks(PPTimeTicksToEventTime(event_now));
+  EXPECT_GE(kTimeSecondsSlop, fabs(converted - event_now));
+
+  // Units should be in seconds.
+  base::Time one_second_from_now = now + base::TimeDelta::FromSeconds(1);
+  double event_one_second_from_now = one_second_from_now.ToDoubleT();
+  EXPECT_GE(kTimeSecondsSlop,
+            1.0 - EventTimeToPPTimeTicks(event_one_second_from_now) -
+                EventTimeToPPTimeTicks(event_now));
+}
+
+}  // namespace ppapi
+}  // namespace webkit