Make Windows TTS PlatformImpl a leaky instance

This CL is making the TtsPlatformImpl instance a leaky
instance since the singleton is alive for the whole
duration of the process.

The use of WeakPtr is no longer required.

Bug: 1133813
Change-Id: Iceeb676cd23a1867132255b51c4fb3439e049985
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441674
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: François Doray <fdoray@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#812791}

content/browser/speech/tts_win.cc

@@ -12,7 +12,7 @@
 
 #include "base/bind.h"
 #include "base/macros.h"
-#include "base/memory/singleton.h"
+#include "base/no_destructor.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/utf_string_conversions.h"
@@ -34,6 +34,9 @@ const wchar_t kLanguageValue[] = L"Language";
 
 class TtsPlatformImplWin : public TtsPlatformImpl {
  public:
+  TtsPlatformImplWin(const TtsPlatformImplWin&) = delete;
+  TtsPlatformImplWin& operator=(const TtsPlatformImplWin&) = delete;
+
   bool PlatformImplAvailable() override { return true; }
 
   void Speak(int utterance_id,
@@ -59,8 +62,8 @@ class TtsPlatformImplWin : public TtsPlatformImpl {
   static void __stdcall SpeechEventCallback(WPARAM w_param, LPARAM l_param);
 
  private:
+  friend base::NoDestructor<TtsPlatformImplWin>;
   TtsPlatformImplWin();
-  ~TtsPlatformImplWin() override {}
 
   void OnSpeechEvent();
 
@@ -77,19 +80,13 @@ class TtsPlatformImplWin : public TtsPlatformImpl {
 
   // These apply to the current utterance only.
   std::wstring utterance_;
-  int utterance_id_;
-  int prefix_len_;
-  ULONG stream_number_;
-  int char_position_;
-  int char_length_;
-  bool paused_;
+  int utterance_id_ = 0;
+  int prefix_len_ = 0;
+  ULONG stream_number_ = 0u;
+  int char_position_ = 0;
+  int char_length_ = 0;
+  bool paused_ = false;
   std::string last_voice_name_;
-
-  friend struct base::DefaultSingletonTraits<TtsPlatformImplWin>;
-
-  base::WeakPtrFactory<TtsPlatformImplWin> weak_factory_{this};
-
-  DISALLOW_COPY_AND_ASSIGN(TtsPlatformImplWin);
 };
 
 // static
@@ -107,7 +104,7 @@ void TtsPlatformImplWin::Speak(
   // Parse SSML and process speech.
   TtsController::GetInstance()->StripSSML(
       utterance, base::BindOnce(&TtsPlatformImplWin::ProcessSpeech,
-                                weak_factory_.GetWeakPtr(), utterance_id, lang,
+                                base::Unretained(this), utterance_id, lang,
                                 voice, params, std::move(on_speak_finished)));
 }
 
@@ -333,12 +330,7 @@ void TtsPlatformImplWin::SetVoiceFromName(const std::string& name) {
   }
 }
 
-TtsPlatformImplWin::TtsPlatformImplWin()
-    : utterance_id_(0),
-      prefix_len_(0),
-      stream_number_(0),
-      char_position_(0),
-      paused_(false) {
+TtsPlatformImplWin::TtsPlatformImplWin() {
   ::CoCreateInstance(CLSID_SpVoice, nullptr, CLSCTX_ALL,
                      IID_PPV_ARGS(&speech_synthesizer_));
   if (speech_synthesizer_.Get()) {
@@ -354,8 +346,8 @@ TtsPlatformImplWin::TtsPlatformImplWin()
 
 // static
 TtsPlatformImplWin* TtsPlatformImplWin::GetInstance() {
-  return base::Singleton<TtsPlatformImplWin,
-                         base::LeakySingletonTraits<TtsPlatformImplWin>>::get();
+  static base::NoDestructor<TtsPlatformImplWin> tts_platform;
+  return tts_platform.get();
 }
 
 // static