Reland #2: Add a short term solution to fix OSX 10.11 system font rendering problems.

Source/platform/mac/VersionUtilMac.mm

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "config.h"
 #import "platform/mac/VersionUtilMac.h"
 
 #include <sstream>
 #include <string>
 #include <sys/utsname.h>
@@ skipping 42 matching lines @@
 // in 10.y or 10.y.z.
 int MacOSXMinorVersion()
 {
     static int minorVersion = MacOSXMinorVersionInternal();
     return minorVersion;
 }
 
 enum {
     LION_MINOR_VERSION = 7,
     MAVERICKS_MINOR_VERSION = 9,
+    YOSEMITE_MINOR_VERSION = 10,
+    EL_CAPITAN_MINOR_VERSION = 11,
 };
 
 } // namespace
 
 namespace blink {
 
 bool IsOSLionOrEarlier()
 {
     return MacOSXMinorVersion() <= LION_MINOR_VERSION;
 }
 
 bool IsOSMavericksOrEarlier()
 {
     return MacOSXMinorVersion() <= MAVERICKS_MINOR_VERSION;
 }
 
 bool IsOSMavericks()
 {
     return MacOSXMinorVersion() == MAVERICKS_MINOR_VERSION;
 }
 
+bool IsOSYosemite()
+{
+    return MacOSXMinorVersion() == YOSEMITE_MINOR_VERSION;
+}
+
+bool IsOSElCapitan()
+{
+    return MacOSXMinorVersion() == EL_CAPITAN_MINOR_VERSION;
+}
+
 } // namespace blink