Add a QuicChromiumClock and make QuicClock abstract to match internal code.

net/quic/platform/api/quic_clock.cc

Index: net/quic/platform/api/quic_clock.cc
diff --git a/net/quic/platform/impl/quic_clock.cc b/net/quic/platform/api/quic_clock.cc
similarity index 65%
rename from net/quic/platform/impl/quic_clock.cc
rename to net/quic/platform/api/quic_clock.cc
index 42b9884acfddef8b279095a55e426e73e4deb3c1..4c52c3e022ff486b80a91119bd5b70c8de323516 100644
--- a/net/quic/platform/impl/quic_clock.cc
+++ b/net/quic/platform/api/quic_clock.cc
@@ -4,29 +4,12 @@
 
 #include "net/quic/platform/api/quic_clock.h"
 
-#include "base/time/time.h"
-
 namespace net {
 
 QuicClock::QuicClock() {}
 
 QuicClock::~QuicClock() {}
 
-QuicTime QuicClock::ApproximateNow() const {
-  // At the moment, Chrome does not have a distinct notion of ApproximateNow().
-  // We should consider implementing this using MessageLoop::recent_time_.
-  return Now();
-}
-
-QuicTime QuicClock::Now() const {
-  return QuicTime(base::TimeTicks::Now());
-}
-
-QuicWallTime QuicClock::WallNow() const {
-  return QuicWallTime::FromUNIXMicroseconds(base::Time::Now().ToJavaTime() *
-                                            1000);
-}
-
 QuicTime QuicClock::ConvertWallTimeToQuicTime(

[Jana, 2016/12/03 19:32:19]

Since all methods except for this one are pure virtual, I'm tempted to try and
make QuicClock an Interface class...  you make this method a utility method
outside of QuicClock, and make this class QuicClockInterface?

     const QuicWallTime& walltime) const {
   //     ..........................