Index: lib/sanitizer_common/sanitizer_symbolizer.h
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer.h
+++ lib/sanitizer_common/sanitizer_symbolizer.h
@@ -75,7 +75,7 @@
 
 class SymbolizerTool;
 
-class Symbolizer {
+class Symbolizer final {
  public:
   /// Initialize and return platform-specific implementation of symbolizer
   /// (if it wasn't already initialized).
@@ -146,8 +146,8 @@
   bool modules_fresh_;
 
   // Platform-specific default demangler, must not return nullptr.
-  virtual const char *PlatformDemangle(const char *name) { UNIMPLEMENTED(); }
-  virtual void PlatformPrepareForSandboxing() { UNIMPLEMENTED(); }
+  const char *PlatformDemangle(const char *name);
+  void PlatformPrepareForSandboxing();
 
   static Symbolizer *symbolizer_;
   static StaticSpinMutex init_mu_;
@@ -160,7 +160,6 @@
   typedef IntrusiveList<SymbolizerTool>::Iterator Iterator;
   IntrusiveList<SymbolizerTool> tools_;
 
- protected:
   explicit Symbolizer(IntrusiveList<SymbolizerTool> tools);
 
   static LowLevelAllocator symbolizer_allocator_;
Index: lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
+++ lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
@@ -349,23 +349,16 @@
 
 #endif  // SANITIZER_SUPPORTS_WEAK_HOOKS
 
-class POSIXSymbolizer : public Symbolizer {
- public:
-  explicit POSIXSymbolizer(IntrusiveList<SymbolizerTool> tools)
-      : Symbolizer(tools) {}
-
- private:
-  const char *PlatformDemangle(const char *name) override {
-    return DemangleCXXABI(name);
-  }
+const char *Symbolizer::PlatformDemangle(const char *name) {
+  return DemangleCXXABI(name);
+}
 
-  void PlatformPrepareForSandboxing() override {
+void Symbolizer::PlatformPrepareForSandboxing() {
 #if SANITIZER_LINUX && !SANITIZER_ANDROID
-    // Cache /proc/self/exe on Linux.
-    CacheBinaryName();
+  // Cache /proc/self/exe on Linux.
+  CacheBinaryName();
 #endif
-  }
-};
+}
 
 static SymbolizerTool *ChooseExternalSymbolizer(LowLevelAllocator *allocator) {
   const char *path = common_flags()->external_symbolizer_path;
@@ -448,7 +441,7 @@
   IntrusiveList<SymbolizerTool> list;
   list.clear();
   ChooseSymbolizerTools(&list, &symbolizer_allocator_);
-  return new(symbolizer_allocator_) POSIXSymbolizer(list);
+  return new(symbolizer_allocator_) Symbolizer(list);
 }
 
 }  // namespace __sanitizer
Index: lib/sanitizer_common/sanitizer_symbolizer_win.cc
===================================================================
--- lib/sanitizer_common/sanitizer_symbolizer_win.cc
+++ lib/sanitizer_common/sanitizer_symbolizer_win.cc
@@ -129,22 +129,19 @@
     return name;
 }
 
-// TODO(kuba.brecka): To be merged with POSIXSymbolizer.
-class WinSymbolizer : public Symbolizer {
- public:
-  explicit WinSymbolizer(IntrusiveList<SymbolizerTool> tools)
-      : Symbolizer(tools) {}
-
- private:
-  const char *PlatformDemangle(const char *name) override { return name; }
-  void PlatformPrepareForSandboxing() override { }
-};
+const char *Symbolizer::PlatformDemangle(const char *name) {
+  return name;
+}
+
+void Symbolizer::PlatformPrepareForSandboxing() {
+  // Do nothing.
+}
 
 Symbolizer *Symbolizer::PlatformInit() {
   IntrusiveList<SymbolizerTool> list;
   list.clear();
   list.push_back(new(symbolizer_allocator_) WinSymbolizerTool());
-  return new(symbolizer_allocator_) WinSymbolizer(list);
+  return new(symbolizer_allocator_) Symbolizer(list);
 }
 
 }  // namespace __sanitizer