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
Add a space between closing template '>' to unbreak build.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185611 91177308-0d34-0410-b5e6-96231b3b80d8