Move most of FontRenderStyle manipulation code into its own file

third_party/WebKit/Source/platform/blink_platform.gypi

 {
   'includes': [
     'platform_generated.gypi',
   ],
   'variables': {
     'platform_files': [
       'AsyncFileSystemCallbacks.h',
       'CalculationValue.h',
       'CheckedInt.h',
       'ContentDecryptionModuleResult.h',
@@ skipping 430 matching lines @@
       'fonts/TextBlob.h',
       'fonts/UnicodeRangeSet.cpp',
       'fonts/UnicodeRangeSet.h',
       'fonts/UTF16TextIterator.cpp',
       'fonts/UTF16TextIterator.h',
       'fonts/VDMXParser.cpp',
       'fonts/VDMXParser.h',
       'fonts/android/FontCacheAndroid.cpp',
       'fonts/linux/FontCacheLinux.cpp',
       'fonts/linux/FontPlatformDataLinux.cpp',
+      'fonts/linux/FontRenderStyle.cpp',
       'fonts/linux/FontRenderStyle.h',
       'fonts/mac/FontFamilyMatcherMac.h',
       'fonts/mac/FontFamilyMatcherMac.mm',
       'fonts/mac/FontCacheMac.mm',
       'fonts/mac/FontPlatformDataMac.mm',
       'fonts/opentype/OpenTypeCapsSupport.h',
       'fonts/opentype/OpenTypeCapsSupport.cpp',
       'fonts/opentype/OpenTypeCapsSupportMPL.cpp',
       'fonts/opentype/OpenTypeSanitizer.cpp',
       'fonts/opentype/OpenTypeSanitizer.h',
@@ skipping 856 matching lines @@
       ['OS!="mac"',
         {
           'platform_test_files': [
             'scroll/ScrollAnimatorTest.cpp',
           ],
         }
       ],
     ],
   },
 }