base::mac::IsOSSierra() -> base::mac::IsOS10_12(), etc.

third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm

Index: third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm
diff --git a/third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm b/third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm
index c25728eabc1063708f43f52a3d3dda47766bcfa8..6f53a02b7e4a224deba82d9a1e21d0112d4b314c 100644
--- a/third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm
+++ b/third_party/WebKit/Source/platform/fonts/mac/FontFamilyMatcherMac.mm
@@ -138,7 +138,7 @@ NSFont* MatchNSFontFamily(NSString* desiredFamily, NSFontTraitMask desiredTraits
         // so force layout tests to use "Lucida Grande". Once the 10.10 SDK
         // switch is made, this should be changed to return .LucidaGrandeUI and
         // the Layout Expectations should be updated. http://crbug.com/515836.
-        if (LayoutTestSupport::isRunningLayoutTest() && IsOSMavericks()) {
+        if (LayoutTestSupport::isRunningLayoutTest() && IsOS10_9()) {
             if (desiredWeight >= blink::FontWeightBold)
                 return [NSFont fontWithName:@"Lucida Grande Bold" size:size];
             else
@@ -146,7 +146,7 @@ NSFont* MatchNSFontFamily(NSString* desiredFamily, NSFontTraitMask desiredTraits
         }
 
         NSFont* font = nil;
-        if (IsOSMavericks()) {
+        if (IsOS10_9()) {
             // On older OSX versions, only bold and regular are available.
             if (desiredWeight >= blink::FontWeightBold)
                 font = [NSFont boldSystemFontOfSize:size];