Oilpan: prefer eager finalization over prefinalizers.

Source/platform/speech/PlatformSpeechSynthesizer.cpp

Index: Source/platform/speech/PlatformSpeechSynthesizer.cpp
diff --git a/Source/platform/speech/PlatformSpeechSynthesizer.cpp b/Source/platform/speech/PlatformSpeechSynthesizer.cpp
index 9363765d5818ef8fd6f63e21fc983d2972f0b768..9262b0313eedf07e5ba73e58e402e244f5eb218e 100644
--- a/Source/platform/speech/PlatformSpeechSynthesizer.cpp
+++ b/Source/platform/speech/PlatformSpeechSynthesizer.cpp
@@ -48,24 +48,12 @@ PlatformSpeechSynthesizer::PlatformSpeechSynthesizer(PlatformSpeechSynthesizerCl
 {
     m_webSpeechSynthesizerClient = new WebSpeechSynthesizerClientImpl(this, client);
     m_webSpeechSynthesizer = adoptPtr(Platform::current()->createSpeechSynthesizer(m_webSpeechSynthesizerClient));
-    ThreadState::current()->registerPreFinalizer(*this);
 }
 
 PlatformSpeechSynthesizer::~PlatformSpeechSynthesizer()
 {
 }
 
-// Since the m_webSpeechSynthesizer (i.e., TtsDispatcher in the chrome side)
-// holds a raw pointer back to the m_webSpeechSynthesizerClient, we need to
-// make sure that the raw pointer is cleared before the sweeping starts.
-// Otherwise, m_webSpeechSynthesizerClient might end up being lazily swept
-// before this PlatformSpeechSynthesizer object is, leaving
-// m_sweepSpeechSynthesizer with a dangling pointer to a freed object.
-void PlatformSpeechSynthesizer::dispose()
-{
-    m_webSpeechSynthesizer.clear();
-}
-
 void PlatformSpeechSynthesizer::speak(PlatformSpeechSynthesisUtterance* utterance)
 {
     if (m_webSpeechSynthesizer && m_webSpeechSynthesizerClient)