Refactoring of Diagnostic class.

-Move the stuff of Diagnostic related to creating/querying diagnostic IDs into a new DiagnosticIDs class.
-DiagnosticIDs can be shared among multiple Diagnostics for multiple translation units.
-The rest of the state in Diagnostic object is considered related and tied to one translation unit.
-Have Diagnostic point to the SourceManager that is related with. Diagnostic can now accept just a
   SourceLocation instead of a FullSourceLoc.
-Reflect the changes to various interfaces.

llvm-svn: 119730

clang/tools/libclang/CIndexCodeCompletion.cpp

@@ -258,7 +258,9 @@ struct AllocatedCXCodeCompleteResults : public CXCodeCompleteResults {
 static unsigned CodeCompletionResultObjects;
   
 AllocatedCXCodeCompleteResults::AllocatedCXCodeCompleteResults() 
-  : CXCodeCompleteResults(), Diag(new Diagnostic),
+  : CXCodeCompleteResults(),
+    Diag(new Diagnostic(
+                   llvm::IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs))),
     SourceMgr(*Diag, FileMgr, FileSystemOpts) { 
   if (getenv("LIBCLANG_OBJTRACKING")) {
     ++CodeCompletionResultObjects;