[AST] Use ArrayRef in more interfaces

ArrayRef is a little better than passing around a pointer/length
pair.

No functional change is intended.

llvm-svn: 274732
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index f33532e..f4698ee 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -1909,8 +1909,7 @@
       return QualType();
   }
   return Importer.getToContext().getTemplateSpecializationType(ToTemplate, 
-                                                         ToTemplateArgs.data(), 
-                                                         ToTemplateArgs.size(),
+                                                               ToTemplateArgs,
                                                                ToCanonType);
 }