Revert of Add a short term solution to fix OSX 10.11 system font rendering problems.

Source/platform/mac/VersionUtilMac.mm

Index: Source/platform/mac/VersionUtilMac.mm
diff --git a/Source/platform/mac/VersionUtilMac.mm b/Source/platform/mac/VersionUtilMac.mm
index fdafd44713d5ab3ac2fffc4c4e4ba9754b101c1c..29e22f995fbad849512194e6dae6a454c6b8e8e5 100644
--- a/Source/platform/mac/VersionUtilMac.mm
+++ b/Source/platform/mac/VersionUtilMac.mm
@@ -9,10 +9,6 @@
 
 #ifndef NSAppKitVersionNumber10_9
 #define NSAppKitVersionNumber10_9 1265
-#endif
-
-#ifndef NSAppKitVersionNumber10_10
-#define NSAppKitVersionNumber10_10 1343
 #endif
 
 namespace blink {
@@ -27,9 +23,4 @@
     return floor(NSAppKitVersionNumber) == NSAppKitVersionNumber10_9;
 }
 
-bool IsOSYosemiteOrEarlier()
-{
-    return floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10;
-}
-
 } // namespace blink