Add a WebSpeechSynthesisVoice constructor to the public API.

Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp

Index: Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp
diff --git a/Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp b/Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp
index b4c95b977edcd1488930d4a1846ae780a831b6ee..3594794927a9cbfa310a04a26d45e29997b5f48c 100644
--- a/Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp
+++ b/Source/core/platform/chromium/support/WebSpeechSynthesisVoice.cpp
@@ -33,6 +33,11 @@
 
 namespace WebKit {
 
+WebSpeechSynthesisVoice::WebSpeechSynthesisVoice()
+    : m_private(WebCore::PlatformSpeechSynthesisVoice::create())
+{
+}
+
 void WebSpeechSynthesisVoice::assign(const WebSpeechSynthesisVoice& other)
 {
     m_private = other.m_private;