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

Source/platform/mac/VersionUtilMacTest.mm

Index: Source/platform/mac/VersionUtilMacTest.mm
diff --git a/Source/platform/mac/VersionUtilMacTest.mm b/Source/platform/mac/VersionUtilMacTest.mm
index c74a8a2fb8780c09ce8dc604d0745eff004109d3..32c2c7409d53e2df3006fbda211ff5f3bdf05123 100644
--- a/Source/platform/mac/VersionUtilMacTest.mm
+++ b/Source/platform/mac/VersionUtilMacTest.mm
@@ -23,6 +23,11 @@
 // This number was determined by writing a tiny Cocoa App on 10.10.4.
 #define NSAppKitVersionNumber10_10Max 1348
 
+// This number was measured on OSX 10.11 Beta 15A234d. The 10.11
+// AppKit.framework does not provide an NSAppKitVersionNumber preprocessor
+// definition for OSX 10.11.
+#define NSAppKitVersionNumber10_11Max 1389
+
 // AppKit version is loosely correlated to OSX version. It's still useful as a
 // sanity check in unit tests, though we don't want to rely on it in production
 // code.
@@ -32,6 +37,8 @@ TEST(VersionUtilMac, AppKitVersions)
         EXPECT_TRUE(blink::IsOSLionOrEarlier());
         EXPECT_TRUE(blink::IsOSMavericksOrEarlier());
         EXPECT_FALSE(blink::IsOSMavericks());
+        EXPECT_FALSE(blink::IsOSYosemite());
+        EXPECT_FALSE(blink::IsOSElCapitan());
         return;
     }
 
@@ -39,19 +46,36 @@ TEST(VersionUtilMac, AppKitVersions)
         EXPECT_FALSE(blink::IsOSLionOrEarlier());
         EXPECT_TRUE(blink::IsOSMavericksOrEarlier());
         EXPECT_FALSE(blink::IsOSMavericks());
+        EXPECT_FALSE(blink::IsOSYosemite());
+        EXPECT_FALSE(blink::IsOSElCapitan());
         return;
     }
+
     if (floor(NSAppKitVersionNumber) == NSAppKitVersionNumber10_9) {
         EXPECT_FALSE(blink::IsOSLionOrEarlier());
         EXPECT_TRUE(blink::IsOSMavericksOrEarlier());
         EXPECT_TRUE(blink::IsOSMavericks());
+        EXPECT_FALSE(blink::IsOSYosemite());
+        EXPECT_FALSE(blink::IsOSElCapitan());
         return;
     }
+
     if (floor(NSAppKitVersionNumber) <= NSAppKitVersionNumber10_10Max &&
         floor(NSAppKitVersionNumber) >=  NSAppKitVersionNumber10_10) {
         EXPECT_FALSE(blink::IsOSLionOrEarlier());
         EXPECT_FALSE(blink::IsOSMavericksOrEarlier());
         EXPECT_FALSE(blink::IsOSMavericks());
+        EXPECT_TRUE(blink::IsOSYosemite());
+        EXPECT_FALSE(blink::IsOSElCapitan());
+        return;
+    }
+
+    if (floor(NSAppKitVersionNumber) == NSAppKitVersionNumber10_11Max) {
+        EXPECT_FALSE(blink::IsOSLionOrEarlier());
+        EXPECT_FALSE(blink::IsOSMavericksOrEarlier());
+        EXPECT_FALSE(blink::IsOSMavericks());
+        EXPECT_FALSE(blink::IsOSYosemite());
+        EXPECT_TRUE(blink::IsOSElCapitan());
         return;
     }
 }