Simplify use of TextDirection enum.

Source/platform/fonts/mac/ComplexTextController.cpp

Index: Source/platform/fonts/mac/ComplexTextController.cpp
diff --git a/Source/platform/fonts/mac/ComplexTextController.cpp b/Source/platform/fonts/mac/ComplexTextController.cpp
index e325daebffd8559ea5653682f54aa138d3e9a9f8..c84d2a58da7b8eaf5107a2d9c2f255ac396cefe4 100644
--- a/Source/platform/fonts/mac/ComplexTextController.cpp
+++ b/Source/platform/fonts/mac/ComplexTextController.cpp
@@ -83,9 +83,9 @@ ComplexTextController::ComplexTextController(const Font* font, const TextRun& ru
         bool isAfterExpansion = m_afterExpansion;
         unsigned expansionOpportunityCount;
         if (m_run.is8Bit())
-            expansionOpportunityCount = Character::expansionOpportunityCount(m_run.characters8(), m_end, m_run.ltr() ? LTR : RTL, isAfterExpansion);
+            expansionOpportunityCount = Character::expansionOpportunityCount(m_run.characters8(), m_end, m_run.direction(), isAfterExpansion);
          else
-            expansionOpportunityCount = Character::expansionOpportunityCount(m_run.characters16(), m_end, m_run.ltr() ? LTR : RTL, isAfterExpansion);
+            expansionOpportunityCount = Character::expansionOpportunityCount(m_run.characters16(), m_end, m_run.direction(), isAfterExpansion);
         if (isAfterExpansion && !m_run.allowsTrailingExpansion())
             expansionOpportunityCount--;