Fix the aec dump crash when users disable aec dump without closing the "Save File" overlay.

content/browser/media/webrtc_internals.cc

Index: content/browser/media/webrtc_internals.cc
diff --git a/content/browser/media/webrtc_internals.cc b/content/browser/media/webrtc_internals.cc
index d85c5548970c9f71258bbf17322b8a6b3e23499b..f45f192cfa268b04d747906bac4e8f8f43dadd6c 100644
--- a/content/browser/media/webrtc_internals.cc
+++ b/content/browser/media/webrtc_internals.cc
@@ -246,6 +246,10 @@ void WebRTCInternals::EnableAecDump(content::WebContents* web_contents) {
 void WebRTCInternals::DisableAecDump() {
 #if defined(ENABLE_WEBRTC)
   aec_dump_enabled_ = false;
+
+  // Tear down the dialog since the user has unchecked the AEC dump box.
+  select_file_dialog_ = NULL;
+
   for (RenderProcessHost::iterator i(
            content::RenderProcessHost::AllHostsIterator());
        !i.IsAtEnd(); i.Advance()) {