[clang] [clang][deps] Make dependency directives getter thread-safe (PR #136178)

[Cyndy Ishida via cfe-commits]

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@@ -357,6 +357,32 @@ static void canonicalizeDefines(PreprocessorOptions &PPOpts) {
   std::swap(PPOpts.Macros, NewMacros);
 }
 
+class ActualDependencyDirectivesGetter : public DependencyDirectivesGetter {
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cyndyishida wrote:

nit: s/ActualDependencyDirectivesGetter/DSWDependencyDirectivesGetter ? or maybe `ScanningDependencyDirectivesGetter`

https://github.com/llvm/llvm-project/pull/136178