Fixes crash in AudioManagerMac at shutdown

media/audio/mac/audio_manager_mac.cc

Index: media/audio/mac/audio_manager_mac.cc
diff --git a/media/audio/mac/audio_manager_mac.cc b/media/audio/mac/audio_manager_mac.cc
index cbcd5edefecea52b958ec0edfdeed507838b1149..bdc01f5e65c07596a25be5f2a9698a1b8718a0ed 100644
--- a/media/audio/mac/audio_manager_mac.cc
+++ b/media/audio/mac/audio_manager_mac.cc
@@ -390,7 +390,8 @@ AudioManagerMac::~AudioManagerMac() {
   // might remain even at this late state.
   // TODO(henrika): figure out the real cause why streams are not closed
   // properly by the AIC for all cases and then remove this loop.
-  for (auto* stream : low_latency_input_streams_) {
+  auto low_latency_input_streams_copy = low_latency_input_streams_;

[tommi (sloooow) - chröme, 2016/07/08 12:06:59]

nit: add a comment above this line that explains why this is needed.  Something
like:

// |low_latency_input_streams_| will be modified during the call to
stream->Close(), so
// we can't iterate over it here.  Instead iterate over a copy.

[henrika (OOO until Aug 14), 2016/07/08 12:19:38]

Good idea, thanks!

+  for (auto* stream : low_latency_input_streams_copy) {
     LOG(WARNING) << "Closing existing audio input stream at destruction";
     // Prevents active Core Audio callbacks to use possibly invalid objects
     // in its OnData() callback.