Implemented ScopedFakeTime, faking rtc::TimeNanos.

webrtc/base/timeutils.cc

Index: webrtc/base/timeutils.cc
diff --git a/webrtc/base/timeutils.cc b/webrtc/base/timeutils.cc
index a9fe49d6075a2341a387247ccb8e941677ee3544..51e36d0bdae1f18ed895ce97d657523eaf430a84 100644
--- a/webrtc/base/timeutils.cc
+++ b/webrtc/base/timeutils.cc
@@ -30,7 +30,24 @@
 
 namespace rtc {
 
+namespace test {
+
+namespace {
+FakeTimeInterface* global_fake_time = nullptr;

[pbos-webrtc, 2016/05/31 22:34:16]

g_fake_time

[nisse-webrtc, 2016/06/01 07:35:35]

Done.

+}  // Anonymous
+
+void SetFakeTime(FakeTimeInterface* fake_time) {
+  // Allow setting fake_time only if it is null.
+  RTC_CHECK(!global_fake_time || !fake_time);

[pbos-webrtc, 2016/05/31 22:34:16]

if (!fake_time)
  RTC_CHECK(!global_fake_time);

Reads easier to me.

[nisse-webrtc, 2016/06/01 07:35:35]

Changed to

  if (fake_time)
    RTC_CHECK(!g_fake_time);

+  global_fake_time = fake_time;
+}
+
+}  // namespace test
+
 uint64_t TimeNanos() {
+  if (test::global_fake_time)
+    return test::global_fake_time->TimeNanos();
+
   int64_t ticks = 0;
 #if defined(WEBRTC_MAC)
   static mach_timebase_info_data_t timebase;