[clang] [clang][DependencyScanning] Implementation of `CompilerInstanceWithContext` to Improve By-Name Queries (PR #164345)

[Jan Svoboda via cfe-commits]

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@@ -87,6 +88,9 @@ class DependencyCollector {
                                   bool IsSystem, bool IsModuleFile,
                                   bool IsMissing);
 
+  /// @return the PPCallback this collector added to the Preprocessor.
+  virtual PPCallbacks *getPPCallbacks() { return nullptr; };
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jansvoboda11 wrote:

Do we need this new interface? It's only implemented by single derived class that we have available in the spot where we call `getPPCallbacks()`.

https://github.com/llvm/llvm-project/pull/164345