Make ChromeOS 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: I311e8bd354523be7cbdb07d0e87876141ec5e81d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2441967Reviewed-by: François Doray <fdoray@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Etienne Bergeron <etienneb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#813301}

chrome/browser/speech/tts_chromeos.cc

@@ -11,8 +11,7 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/tts_platform.h"
 
-TtsPlatformImplChromeOs::TtsPlatformImplChromeOs() {}
-TtsPlatformImplChromeOs::~TtsPlatformImplChromeOs() {}
+TtsPlatformImplChromeOs::TtsPlatformImplChromeOs() = default;
 
 bool TtsPlatformImplChromeOs::PlatformImplAvailable() {
   return arc::ArcServiceManager::Get() && arc::ArcServiceManager::Get()
@@ -42,7 +41,7 @@ void TtsPlatformImplChromeOs::Speak(
   // Parse SSML and process speech.
   content::TtsController::GetInstance()->StripSSML(
       utterance, base::BindOnce(&TtsPlatformImplChromeOs::ProcessSpeech,
-                                weak_factory_.GetWeakPtr(), utterance_id, lang,
+                                base::Unretained(this), utterance_id, lang,
                                 voice, params, std::move(on_speak_finished)));
 }
 
@@ -117,5 +116,6 @@ bool TtsPlatformImplChromeOs::IsSpeaking() {
 // static
 TtsPlatformImplChromeOs*
 TtsPlatformImplChromeOs::GetInstance() {
-  return base::Singleton<TtsPlatformImplChromeOs>::get();
+  static base::NoDestructor<TtsPlatformImplChromeOs> tts_platform;
+  return tts_platform.get();
 }

chrome/browser/speech/tts_chromeos.h

@@ -6,12 +6,16 @@
 #define CHROME_BROWSER_SPEECH_TTS_CHROMEOS_H_
 
 #include "base/macros.h"
+#include "base/no_destructor.h"
 #include "content/public/browser/tts_platform.h"
 
 // This class includes extension-based tts through LoadBuiltInTtsExtension and
 // native tts through ARC.
 class TtsPlatformImplChromeOs : public content::TtsPlatform {
  public:
+  TtsPlatformImplChromeOs(const TtsPlatformImplChromeOs&) = delete;
+  TtsPlatformImplChromeOs& operator=(const TtsPlatformImplChromeOs&) = delete;
+
   // TtsPlatform overrides:
   bool PlatformImplAvailable() override;
   bool LoadBuiltInTtsEngine(content::BrowserContext* browser_context) override;
@@ -39,8 +43,8 @@ class TtsPlatformImplChromeOs : public content::TtsPlatform {
   static TtsPlatformImplChromeOs* GetInstance();
 
  private:
+  friend base::NoDestructor<TtsPlatformImplChromeOs>;
   TtsPlatformImplChromeOs();
-  virtual ~TtsPlatformImplChromeOs();
 
   void ProcessSpeech(int utterance_id,
                      const std::string& lang,
@@ -49,13 +53,7 @@ class TtsPlatformImplChromeOs : public content::TtsPlatform {
                      base::OnceCallback<void(bool)> on_speak_finished,
                      const std::string& parsed_utterance);
 
-  friend struct base::DefaultSingletonTraits<TtsPlatformImplChromeOs>;
-
   std::string error_;
-
-  base::WeakPtrFactory<TtsPlatformImplChromeOs> weak_factory_{this};
-
-  DISALLOW_COPY_AND_ASSIGN(TtsPlatformImplChromeOs);
 };
 
 #endif  // CHROME_BROWSER_SPEECH_TTS_CHROMEOS_H_