Blink Platform: Remove time functions from Platform.

third_party/WebKit/Source/wtf/CurrentTime.h

Index: third_party/WebKit/Source/wtf/CurrentTime.h
diff --git a/third_party/WebKit/Source/wtf/CurrentTime.h b/third_party/WebKit/Source/wtf/CurrentTime.h
index e41ccad8755e3803efcb9a4f8cedc4c3e53cdd02..a7e9829c5c011e71f1ba4ad2aabde9687019c427 100644
--- a/third_party/WebKit/Source/wtf/CurrentTime.h
+++ b/third_party/WebKit/Source/wtf/CurrentTime.h
@@ -51,14 +51,19 @@ inline double currentTimeMS()
 // On unsupported platforms, this function only guarantees the result will be non-decreasing.
 WTF_EXPORT double monotonicallyIncreasingTime();
 
-typedef double(*TimeFunction)(void);
-void setCurrentTimeFunction(TimeFunction);
-WTF_EXPORT void setMonotonicallyIncreasingTimeFunction(TimeFunction);
+using TimeFunction = double (*)();
+
+// Make all the time functions (currentTime(), monotonicallyIncreasingTime(), systemTraceTime()) return the result
+// of the supplied function. Returns the pointer to the old time function. For both setting and getting, nullptr means
+// using the default timing function returning the actual time.
+WTF_EXPORT TimeFunction setTimeFunctionsForTesting(TimeFunction);
 
 } // namespace WTF
 
 using WTF::currentTime;
 using WTF::currentTimeMS;
 using WTF::monotonicallyIncreasingTime;
+using WTF::TimeFunction;
+using WTF::setTimeFunctionsForTesting;
 
 #endif // CurrentTime_h