Use SmallVectorImpl instead of SmallVector for iterators and references to avoid specifying the vector size unnecessarily.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185610 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndex.cpp b/tools/libclang/CIndex.cpp
index 09bb0eb..eecb16a 100644
--- a/tools/libclang/CIndex.cpp
+++ b/tools/libclang/CIndex.cpp
@@ -308,8 +308,8 @@
 
   bool VisitedAtLeastOnce = false;
   DeclContext *CurDC = 0;
-  SmallVector<Decl *, 16>::iterator DIt = Decls.begin();
-  for (SmallVector<Decl *, 16>::iterator DE = Decls.end(); DIt != DE; ++DIt) {
+  SmallVectorImpl<Decl *>::iterator DIt = Decls.begin();
+  for (SmallVectorImpl<Decl *>::iterator DE = Decls.end(); DIt != DE; ++DIt) {
     Decl *D = *DIt;
     if (D->getSourceRange().isInvalid())
       continue;