Revert of Improving the fake clock and using it to fix a flaky STUN timeout test.

webrtc/base/fakeclock.h

Index: webrtc/base/fakeclock.h
diff --git a/webrtc/base/fakeclock.h b/webrtc/base/fakeclock.h
index 4aecc54cc4ffee3e894cd4fef97760fce69338e8..2b3afdde05f684926621bcc95c2f917bfb7bd60f 100644
--- a/webrtc/base/fakeclock.h
+++ b/webrtc/base/fakeclock.h
@@ -19,8 +19,6 @@
 
 // Fake clock for use with unit tests, which does not tick on its own.
 // Starts at time 0.
-//
-// TODO(deadbeef): Unify with webrtc::SimulatedClock.
 class FakeClock : public ClockInterface {
  public:
   ~FakeClock() override {}
@@ -40,17 +38,6 @@
   uint64_t time_ GUARDED_BY(lock_) = 0u;
 };
 
-// Helper class that sets itself as the global clock in its constructor and
-// unsets it in its destructor.
-class ScopedFakeClock : public FakeClock {
- public:
-  ScopedFakeClock();
-  ~ScopedFakeClock() override;
-
- private:
-  ClockInterface* prev_clock_;
-};
-
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_FAKECLOCK_H_