Description: revert https://gn.googlesource.com/gn/+/8730b0feb6b991fa47368566501ab9ccfb453c92, which breaks the chromium build

--- a/tools/gn/tools/gn/binary_target_generator.cc
+++ b/tools/gn/tools/gn/binary_target_generator.cc
@@ -68,38 +68,6 @@ void BinaryTargetGenerator::DoRun() {
     return;
 }
 
-bool BinaryTargetGenerator::FillSources() {
-  bool ret = TargetGenerator::FillSources();
-  for (std::size_t i = 0; i < target_->sources().size(); ++i) {
-    const auto& source = target_->sources()[i];
-    switch (source.type()) {
-      case SourceFile::SOURCE_CPP:
-      case SourceFile::SOURCE_H:
-      case SourceFile::SOURCE_C:
-      case SourceFile::SOURCE_M:
-      case SourceFile::SOURCE_MM:
-      case SourceFile::SOURCE_S:
-      case SourceFile::SOURCE_ASM:
-      case SourceFile::SOURCE_O:
-        // These are allowed.
-        break;
-      case SourceFile::SOURCE_RC:
-      case SourceFile::SOURCE_DEF:
-      case SourceFile::SOURCE_RS:
-      case SourceFile::SOURCE_GO:
-      case SourceFile::SOURCE_UNKNOWN:
-      case SourceFile::SOURCE_NUMTYPES:
-        *err_ =
-            Err(scope_->GetValue(variables::kSources, true)->list_value()[i],
-                std::string("Only source, header, and object files belong in "
-                            "the sources of a ") +
-                    Target::GetStringForOutputType(target_->output_type()) +
-                    ". " + source.value() + " is not one of the valid types.");
-    }
-  }
-  return ret;
-}
-
 bool BinaryTargetGenerator::FillCompleteStaticLib() {
   if (target_->output_type() == Target::STATIC_LIBRARY) {
     const Value* value = scope_->GetValue(variables::kCompleteStaticLib, true);
--- a/tools/gn/tools/gn/binary_target_generator.h
+++ b/tools/gn/tools/gn/binary_target_generator.h
@@ -22,7 +22,6 @@ class BinaryTargetGenerator : public Tar
 
  protected:
   void DoRun() override;
-  bool FillSources() override;
 
  private:
   bool FillCompleteStaticLib();
--- a/tools/gn/tools/gn/source_dir.cc
+++ b/tools/gn/tools/gn/source_dir.cc
@@ -98,10 +98,10 @@ SourceFile SourceDir::ResolveRelativeFil
     return ret;
 
   const std::string& input_string = p.string_value();
-  if (!ValidateResolveInput<std::string>(true, p, input_string, err))
+  if (!ValidateResolveInput<std::string>(true, p, input_string, err)) {
     return ret;
-
-  ret.SetValue(ResolveRelative(input_string, value_, true, source_root));
+  }
+  ret.value_ = ResolveRelative(input_string, value_, true, source_root);
   return ret;
 }
 
--- a/tools/gn/tools/gn/source_file.cc
+++ b/tools/gn/tools/gn/source_file.cc
@@ -55,19 +55,18 @@ SourceFile::Type GetSourceFileType(const
 SourceFile::SourceFile() : type_(SOURCE_UNKNOWN) {}
 
 SourceFile::SourceFile(const base::StringPiece& p)
-    : value_(p.data(), p.size()) {
+    : value_(p.data(), p.size()), type_(GetSourceFileType(value_)) {
   DCHECK(!value_.empty());
   AssertValueSourceFileString(value_);
   NormalizePath(&value_);
-  type_ = GetSourceFileType(value_);
 }
 
-SourceFile::SourceFile(SwapIn, std::string* value) {
+SourceFile::SourceFile(SwapIn, std::string* value)
+    : type_(GetSourceFileType(*value)) {
   value_.swap(*value);
   DCHECK(!value_.empty());
   AssertValueSourceFileString(value_);
   NormalizePath(&value_);
-  type_ = GetSourceFileType(value_);
 }
 
 SourceFile::~SourceFile() = default;
@@ -93,8 +92,3 @@ SourceDir SourceFile::GetDir() const {
 base::FilePath SourceFile::Resolve(const base::FilePath& source_root) const {
   return ResolvePath(value_, true, source_root);
 }
-
-void SourceFile::SetValue(const std::string& value) {
-  value_ = value;
-  type_ = GetSourceFileType(value_);
-}
--- a/tools/gn/tools/gn/source_file.h
+++ b/tools/gn/tools/gn/source_file.h
@@ -97,16 +97,11 @@ class SourceFile {
     return value_ < other.value_;
   }
 
-  void swap(SourceFile& other) {
-    value_.swap(other.value_);
-    std::swap(type_, other.type_);
-  }
+  void swap(SourceFile& other) { value_.swap(other.value_); }
 
  private:
   friend class SourceDir;
 
-  void SetValue(const std::string& value);
-
   std::string value_;
   Type type_;
 
--- a/tools/gn/tools/gn/target_generator.h
+++ b/tools/gn/tools/gn/target_generator.h
@@ -47,7 +47,7 @@ class TargetGenerator {
 
   const BuildSettings* GetBuildSettings() const;
 
-  virtual bool FillSources();
+  bool FillSources();
   bool FillPublic();
   bool FillConfigs();
   bool FillOutputs(bool allow_substitutions);