[llvm-cov] Create directory structure when filtering using -name*= options

Before this change using any of the -name*= command line options with an output
directory would result in a single file (functions.txt/functions.html)
containing the coverage for those specific functions. Now you get the same
directory structure as when not using any -name*= options.

Differential Revision: https://reviews.llvm.org/D38280

llvm-svn: 314396
diff --git a/llvm/tools/llvm-cov/SourceCoverageViewHTML.h b/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
index 8cb7356..e11111a 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
+++ b/llvm/tools/llvm-cov/SourceCoverageViewHTML.h
@@ -29,7 +29,8 @@
   void closeViewFile(OwnedStream OS) override;
 
   Error createIndexFile(ArrayRef<std::string> SourceFiles,
-                        const coverage::CoverageMapping &Coverage) override;
+                        const coverage::CoverageMapping &Coverage,
+                        const CoverageFilter &Filters) override;
 
   CoveragePrinterHTML(const CoverageViewOptions &Opts)
       : CoveragePrinter(Opts) {}