[ASTContext] Remove unused function and includes

(cherry picked from commit acd4cb1)

Author: rintaro

include/swift/AST/ASTContext.h

@@ -892,10 +892,6 @@ class ASTContext final {
     return getIdentifier(getSwiftName(kind));
   }
 
-  /// Collect visible clang modules from the ClangModuleLoader. These modules are
-  /// not necessarily loaded.
-  void getVisibleTopLevelClangModules(SmallVectorImpl<clang::Module*> &Modules) const;
-
   /// Populate \p names with visible top level module names.
   /// This guarantees that resulted \p names doesn't have duplicated names.
   void getVisibleTopLevelModuleNames(SmallVectorImpl<Identifier> &names) const;

lib/AST/ASTContext.cpp

@@ -46,10 +46,6 @@
 #include "swift/Syntax/SyntaxArena.h"
 #include "swift/Strings.h"
 #include "swift/Subsystems.h"
-#include "clang/AST/Attr.h"
-#include "clang/AST/DeclObjC.h"
-#include "clang/Lex/HeaderSearch.h"
-#include "clang/Lex/Preprocessor.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringMap.h"
@@ -1502,12 +1498,6 @@ ModuleDecl *ASTContext::getLoadedModule(Identifier ModuleName) const {
   return LoadedModules.lookup(ModuleName);
 }
 
-void ASTContext::getVisibleTopLevelClangModules(
-    SmallVectorImpl<clang::Module*> &Modules) const {
-  getClangModuleLoader()->getClangPreprocessor().getHeaderSearchInfo().
-    collectAllModules(Modules);
-}
-
 static AllocationArena getArena(GenericSignature *genericSig) {
   if (!genericSig)
     return AllocationArena::Permanent;

lib/Serialization/SerializedModuleLoader.cpp

@@ -72,8 +72,7 @@ Optional<bool> forEachModuleSearchPath(
       return result;
 
   // Apple platforms have extra implicit framework search paths:
-  // $SDKROOT/System/Library/Frameworks/ ; and
-  // $SDKROOT/Library/Frameworks/
+  // $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
   if (Ctx.LangOpts.Target.isOSDarwin()) {
     SmallString<128> scratch;
     scratch = Ctx.SearchPathOpts.SDKPath;
@@ -154,7 +153,7 @@ void SerializedModuleLoaderBase::collectVisibleTopLevelModuleNamesImpl(
     switch (Kind) {
     case SearchPathKind::Import: {
       // Look for:
-      // $PATH/{name}.swiftmodule/{arch}.{extension} ; Or
+      // $PATH/{name}.swiftmodule/{arch}.{extension} or
       // $PATH/{name}.{extension}
       forEachDirectoryEntryPath(searchPath, [&](StringRef path) {
         auto pathExt = llvm::sys::path::extension(path);