llvm-cov: Rename MappingRegion to coverage::CountedRegion (NFC)

This name was too similar to CoverageMappingRegion, and the type
really belongs in the coverage library anyway.

llvm-svn: 217416
diff --git a/llvm/tools/llvm-cov/SourceCoverageDataManager.h b/llvm/tools/llvm-cov/SourceCoverageDataManager.h
index f389cad..148ff94 100644
--- a/llvm/tools/llvm-cov/SourceCoverageDataManager.h
+++ b/llvm/tools/llvm-cov/SourceCoverageDataManager.h
@@ -64,7 +64,7 @@
 public:
   SourceCoverageDataManager() : Uniqued(false) {}
 
-  void insert(const MappingRegion &Region);
+  void insert(const coverage::CountedRegion &CR);
 
   /// \brief Return the source ranges and execution counts
   /// obtained from the non-skipped mapping regions.