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

The mechanism that Blink was using to determine OSX version number was not
reliable. This has since been fixed.

> I landed a CL (https://codereview.chromium.org/1276003003/) which fixes system
> font problems on OSX 10.9 and OSX 10.10. The CL also fixed MatchNSFontFamily()
> to correctly return the system font on 10.11, but this causes glyph rendering
> problems. In the short term, I'm adding logic to MatchNSFontFamily() to return
> nil on 10.11, which was the original behavior before I landed that CL.
>
> BUG=521034
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=200618

BUG=521034
TBR=tkent@chromium.org, keishi@chromium.org

Review URL: https://codereview.chromium.org/1299713004

git-svn-id: svn://svn.chromium.org/blink/trunk@200855 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -133,6 +133,15 @@ static BOOL betterChoice(NSFontTraitMask desiredTraits, int desiredWeight,
 NSFont* MatchNSFontFamily(NSString* desiredFamily, NSFontTraitMask desiredTraits, FontWeight desiredWeight, float size)
 {
     if ([desiredFamily isEqualToString:@"BlinkMacSystemFont"]) {
+        // On OSX 10.11, returning the default system font causes rendering
+        // problems. In the short term, return nil, which is what would be
+        // returned if "BlinkMacSystemFont" was never introduced.
+        // TODO(erikchen): Fix the rendering problems.
+        // http://crbug.com/521034.
+        if (IsOSElCapitan()) {
+            return nil;
+        }
+
         // On OSX 10.9, the default system font depends on the SDK version. When
         // compiled against the OSX 10.10 SDK, the font is .LucidaGrandeUI. When
         // compiled against the OSX 10.6 SDK, the font is Lucida Grande. Layout

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

@@ -24,7 +24,7 @@ void TestSystemFontContainsString(FontWeight desiredWeight, NSString* substring)
 
 TEST(FontFamilyMatcherMacTest, YosemiteFontWeights)
 {
-    if (IsOSMavericksOrEarlier())
+    if (!IsOSYosemite())
         return;
 
     TestSystemFontContainsString(FontWeight100, @"-UltraLight");

third_party/WebKit/Source/platform/mac/VersionUtilMac.h

@@ -16,6 +16,12 @@ PLATFORM_EXPORT bool IsOSLionOrEarlier();
 PLATFORM_EXPORT bool IsOSMavericksOrEarlier();
 PLATFORM_EXPORT bool IsOSMavericks();
 
+// Yosemite is Mac OS X 10.10, Darwin 14.
+PLATFORM_EXPORT bool IsOSYosemite();
+
+// El Capitan is Mac OS X 10.11, Darwin 15.
+PLATFORM_EXPORT bool IsOSElCapitan();
+
 } // namespace blink
 
 #endif // VersionUtilMac_h

third_party/WebKit/Source/platform/mac/VersionUtilMac.mm

@@ -60,6 +60,8 @@ int MacOSXMinorVersion()
 enum {
     LION_MINOR_VERSION = 7,
     MAVERICKS_MINOR_VERSION = 9,
+    YOSEMITE_MINOR_VERSION = 10,
+    EL_CAPITAN_MINOR_VERSION = 11,
 };
 
 } // namespace
@@ -81,4 +83,14 @@ bool IsOSMavericks()
     return MacOSXMinorVersion() == MAVERICKS_MINOR_VERSION;
 }
 
+bool IsOSYosemite()
+{
+    return MacOSXMinorVersion() == YOSEMITE_MINOR_VERSION;
+}
+
+bool IsOSElCapitan()
+{
+    return MacOSXMinorVersion() == EL_CAPITAN_MINOR_VERSION;
+}
+
 } // namespace blink

third_party/WebKit/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;
     }
 }