Convert DCHECK validating that |request_id| was found to a CHECK in SpeechRecognitionDispatcher.

BUG=470777

Review URL: https://codereview.chromium.org/1143913003

Cr-Commit-Position: refs/heads/master@{#330660}

content/renderer/speech_recognition_dispatcher.cc

@@ -313,7 +313,7 @@ void SpeechRecognitionDispatcher::ResetAudioSink() {
 const WebSpeechRecognitionHandle& SpeechRecognitionDispatcher::GetHandleFromID(
     int request_id) {
   HandleMap::iterator iter = handle_map_.find(request_id);
-  DCHECK(iter != handle_map_.end());
+  CHECK(iter != handle_map_.end());
   return iter->second;
 }