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 c0489f5065c68fb619226e8db34f6aa6bff3c5d0..a975ac57a1919228437f2b2931a1398d4ec20791 100644
--- a/third_party/WebKit/Source/wtf/CurrentTime.h
+++ b/third_party/WebKit/Source/wtf/CurrentTime.h
@@ -55,11 +55,12 @@ WTF_EXPORT double monotonicallyIncreasingTime();
 // system.
 WTF_EXPORT double systemTraceTime();
 
-typedef double(*TimeFunction)(void);
-void setCurrentTimeFunction(TimeFunction);
-WTF_EXPORT void setMonotonicallyIncreasingTimeFunction(TimeFunction);
-void setSystemTraceTimeFunction(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
 
@@ -67,5 +68,7 @@ using WTF::currentTime;
 using WTF::currentTimeMS;
 using WTF::monotonicallyIncreasingTime;
 using WTF::systemTraceTime;
+using WTF::TimeFunction;
+using WTF::setTimeFunctionsForTesting;
 
 #endif // CurrentTime_h