Cleanup: Remove unused variables in chrome/ found by Scythe.

chrome/browser/speech/tts_message_filter.h

Index: chrome/browser/speech/tts_message_filter.h
diff --git a/chrome/browser/speech/tts_message_filter.h b/chrome/browser/speech/tts_message_filter.h
index 54314fc876ab0a87e315327846ffe6860dbdda9d..7d4c5fce97f0733b93371312e360393c2571d911 100644
--- a/chrome/browser/speech/tts_message_filter.h
+++ b/chrome/browser/speech/tts_message_filter.h
@@ -23,8 +23,7 @@ class TtsMessageFilter
       public UtteranceEventDelegate,
       public VoicesChangedDelegate {
  public:
-  explicit TtsMessageFilter(int render_process_id,
-      content::BrowserContext* browser_context);
+  explicit TtsMessageFilter(content::BrowserContext* browser_context);
 
   // content::BrowserMessageFilter implementation.
   void OverrideThreadForMessage(const IPC::Message& message,
@@ -67,7 +66,6 @@ class TtsMessageFilter
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
 
-  int render_process_id_;
   content::BrowserContext* browser_context_;
   mutable base::Lock mutex_;
   mutable bool valid_;