Allow two codepaths for PathDiagnostic generation. This patch mainly consists of
refactoring to make this possible (no functionality change).

llvm-svn: 68141
diff --git a/clang/lib/Frontend/PlistDiagnostics.cpp b/clang/lib/Frontend/PlistDiagnostics.cpp
index 007fae8..0c146e5 100644
--- a/clang/lib/Frontend/PlistDiagnostics.cpp
+++ b/clang/lib/Frontend/PlistDiagnostics.cpp
@@ -40,7 +40,9 @@
     ~PlistDiagnostics();
     void HandlePathDiagnostic(const PathDiagnostic* D);
     
+    PathGenerationScheme getGenerationScheme() const { return Extensive; }
     bool supportsLogicalOpControlFlow() const { return true; }
+    bool supportsAllBlockEdges() const { return true; }
   };  
 } // end anonymous namespace