Handle disabled outputs better when enabling.

third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp

Index: third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp
diff --git a/third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp b/third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp
index 89cfd0827f9f5515d3b8a479300c34de45e610eb..f91fbe038bfdc894ff4bcc67b0e4dafce9db55d5 100644
--- a/third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp
+++ b/third_party/WebKit/Source/modules/webaudio/AudioNodeInput.cpp
@@ -94,11 +94,13 @@ void AudioNodeInput::disable(AudioNodeOutput& output) {
 
 void AudioNodeInput::enable(AudioNodeOutput& output) {
   ASSERT(deferredTaskHandler().isGraphOwner());
-  DCHECK(m_disabledOutputs.contains(&output));
 
   // Move output from disabled list to active list.
   m_outputs.add(&output);
-  m_disabledOutputs.remove(&output);
+  if (m_disabledOutputs.size() > 0) {
+    DCHECK(m_disabledOutputs.contains(&output));
+    m_disabledOutputs.remove(&output);
+  }
   changedOutputs();
 
   // Propagate enabled state to outputs.