Move audio output number limit to AudioManager.

media/audio/linux/audio_manager_linux.cc

Index: media/audio/linux/audio_manager_linux.cc
diff --git a/media/audio/linux/audio_manager_linux.cc b/media/audio/linux/audio_manager_linux.cc
index 73f4ace99d359708682604a64511922b579b6153..c875c0816243e37aea708fdb840079f2a8a8374b 100644
--- a/media/audio/linux/audio_manager_linux.cc
+++ b/media/audio/linux/audio_manager_linux.cc
@@ -17,6 +17,9 @@
 
 namespace {
 
+// Maximum number of output streams that can be open simultaneously.
+const size_t kMaxOutputStreams = 50;
+
 const int kMaxInputChannels = 2;
 
 }  // namespace
@@ -44,6 +47,11 @@ AudioOutputStream* AudioManagerLinux::MakeAudioOutputStream(
     return NULL;
   }
 
+  // Don't allow opening more than |kMaxOutputStreams| streams.
+  if (active_streams_.size() >= kMaxOutputStreams) {
+    return NULL;
+  }
+
   std::string device_name = AlsaPcmOutputStream::kAutoSelectDevice;
   if (CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kAlsaOutputDevice)) {