Merge InputSectionData and InputSectionBase.

Now that InputSectionBase is not a template there is no reason to have
the two.

llvm-svn: 295924
diff --git a/lld/ELF/LinkerScript.h b/lld/ELF/LinkerScript.h
index 3735355..6893ad6 100644
--- a/lld/ELF/LinkerScript.h
+++ b/lld/ELF/LinkerScript.h
@@ -35,7 +35,7 @@
 template <class ELFT> class InputSection;
 class OutputSectionBase;
 template <class ELFT> class OutputSectionFactory;
-class InputSectionData;
+class InputSectionBase;
 
 // This represents an expression in the linker script.
 // ScriptParser::readExpr reads an expression and returns an Expr.
@@ -159,7 +159,7 @@
   // will be associated with this InputSectionDescription.
   std::vector<SectionPattern> SectionPatterns;
 
-  std::vector<InputSectionData *> Sections;
+  std::vector<InputSectionBase *> Sections;
 };
 
 // Represents an ASSERT().
@@ -307,7 +307,7 @@
   void output(InputSection<ELFT> *Sec);
   void process(BaseCommand &Base);
   llvm::DenseSet<OutputSectionBase *> AlreadyOutputOS;
-  llvm::DenseSet<InputSectionData *> AlreadyOutputIS;
+  llvm::DenseSet<InputSectionBase *> AlreadyOutputIS;
 };
 
 // Variable template is a C++14 feature, so we can't template