[analyzer] Add checker helpers to CheckerContext.

- Adding Immutable Map to GDM and getIdentifierInfo helper method.

llvm-svn: 166975
diff --git a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
index 510556d..ab1e2a7 100644
--- a/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp
@@ -406,11 +406,13 @@
 
 void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
                                      CheckerContext &C) const {
+  // TODO: Clean up the state.
   for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
          E = SymReaper.dead_end(); I != E; ++I) {
     SymbolRef Sym = *I;
     ProgramStateRef state = C.getState();
     const StreamState *SS = state->get<StreamState>(Sym);
+    // TODO: Shouldn't we have a continue here?
     if (!SS)
       return;