CHECK for adding duplicate converter inputs.

media/base/audio_converter.cc

Index: media/base/audio_converter.cc
diff --git a/media/base/audio_converter.cc b/media/base/audio_converter.cc
index ec74e038a3bc7f4ded3073095fb259d451ec8237..151d88d781aa59e39dc0066d2b77cc02b39241f9 100644
--- a/media/base/audio_converter.cc
+++ b/media/base/audio_converter.cc
@@ -88,6 +88,10 @@ AudioConverter::AudioConverter(const AudioParameters& input_params,
 AudioConverter::~AudioConverter() {}
 
 void AudioConverter::AddInput(InputCallback* input) {
+  // TODO(dalecurtis): Speculative CHECK for http://crbug.com/233026, should be
+  // converted to a DCHECK once resolved.
+  CHECK(std::find(transform_inputs_.begin(), transform_inputs_.end(), input) ==
+        transform_inputs_.end());
   transform_inputs_.push_back(input);
 }