Bug 1502165 - Update cubeb from upstream to 9a7a551. r=kinetik

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 04d58b66057171d25413498b3a4d0607fd500bb8 (2018-10-24 08:43:52 +1300)
+The git commit ID used was 9a7a55153e7f9b9e0036ab023909c7bc4a41688b (2018-10-30 09:05:26 +1300)

media/libcubeb/src/cubeb_audiounit.cpp

@@ -3413,7 +3413,7 @@ audiounit_get_devices_of_type(cubeb_device_type devtype)
   // Remove the aggregate device from the list of devices (if any).
   for (auto it = devices.begin(); it != devices.end();) {
     CFStringRef name = get_device_name(*it);
-    if (CFStringFind(name, CFSTR("CubebAggregateDevice"), 0).location !=
+    if (name && CFStringFind(name, CFSTR("CubebAggregateDevice"), 0).location !=
         kCFNotFound) {
       it = devices.erase(it);
     } else {