[Dependency Scanning] Refactor Clang dependency bridging into a 'ModuleDependencyScanner' utility

This moves the functionality of 'bridgeClangModuleDependency' into a utility in the main scanner class because it relies on various objects whose lifetime is already tied to the scanner itself.

include/swift/AST/ModuleDependencies.h

@@ -23,7 +23,6 @@
 #include "swift/Basic/Assertions.h"
 #include "swift/Basic/CXXStdlibKind.h"
 #include "swift/Basic/LLVM.h"
-#include "swift/ClangImporter/ClangImporter.h"
 #include "swift/Serialization/Validation.h"
 #include "clang/CAS/CASOptions.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
@@ -176,18 +175,6 @@ void registerCxxInteropLibraries(
     const llvm::Triple &Target, StringRef mainModuleName, bool hasStaticCxx,
     bool hasStaticCxxStdlib, CXXStdlibKind cxxStdlibKind,
     std::function<void(const LinkLibrary &)> RegistrationCallback);
-
-using RemapPathCallback = llvm::function_ref<std::string(StringRef)>;
-using LookupModuleOutputCallback =
-    llvm::function_ref<std::string(const clang::tooling::dependencies::ModuleDeps &,
-                                   clang::tooling::dependencies::ModuleOutputKind)>;
-
-ModuleDependencyInfo
-bridgeClangModuleDependency(
-    const ASTContext &ctx,
-    const clang::tooling::dependencies::ModuleDeps &clangDependency,
-    LookupModuleOutputCallback LookupModuleOutput,
-    RemapPathCallback remapPath = nullptr);
 } // namespace dependencies
 
 struct ScannerImportStatementInfo {
@@ -1042,6 +1029,8 @@ using ModuleNameToDependencyMap = llvm::StringMap<ModuleDependencyInfo>;
 using ModuleDependenciesKindMap =
     std::unordered_map<ModuleDependencyKind, ModuleNameToDependencyMap,
                        ModuleDependencyKindHash>;
+using BridgeClangDependencyCallback = llvm::function_ref<ModuleDependencyInfo(
+    const clang::tooling::dependencies::ModuleDeps &clangModuleDep)>;
 
 // MARK: SwiftDependencyScanningService
 /// A carrier of state shared among possibly multiple invocations of the
@@ -1194,9 +1183,8 @@ public:
   /// Record dependencies for the given collection of Clang modules.
   void recordClangDependencies(
       const clang::tooling::dependencies::ModuleDepsGraph &dependencies,
-      const ASTContext &ctx,
-      dependencies::LookupModuleOutputCallback LookupModuleOutput,
-      dependencies::RemapPathCallback remapPath = nullptr);
+      DiagnosticEngine &diags,
+      BridgeClangDependencyCallback bridgeClangModule);
 
   /// Update stored dependencies for the given module.
   void updateDependency(ModuleDependencyID moduleID,