Bug 1400671 - Update cubeb from upstream to ac532ad. r=kinetik

MozReview-Commit-ID: Ek4onH23hPc

media/libcubeb/README_MOZILLA

@@ -5,4 +5,4 @@ Makefile.in build files for the Mozilla build system.
 
 The cubeb git repository is: git://github.com/kinetiknz/cubeb.git
 
-The git commit ID used was 09a90a7817bc3d76723065fdc6b53c542fbed402 (2017-09-13 18:39:50 +0200)
+The git commit ID used was ac532ad4f0defaf7a397db64c2c42d2665cd06e9 (2017-09-17 08:23:45 +1200)

media/libcubeb/src/cubeb_audiounit.cpp

@@ -733,7 +733,12 @@ audiounit_property_listener_callback(AudioObjectID id, UInt32 address_count,
         break;
       case kAudioDevicePropertyDataSource: {
           LOG("Event[%u] - mSelector == kAudioHardwarePropertyDataSource for id=%d", (unsigned int) i, id);
-          switch_side |= DEV_INPUT;
+          if (stm->input_unit) {
+            switch_side |= DEV_INPUT;
+          }
+          if (stm->output_unit) {
+            switch_side |= DEV_OUTPUT;
+          }
         }
         break;
       default: