Set keyboard mic effect if available.

content/browser/renderer_host/media/audio_input_device_manager.h

Index: content/browser/renderer_host/media/audio_input_device_manager.h
diff --git a/content/browser/renderer_host/media/audio_input_device_manager.h b/content/browser/renderer_host/media/audio_input_device_manager.h
index e8d44cb807ab2a188181bd9f4ca88641fa0b4b63..2c633e1c0bb719737146abed1c8689a929214af5 100644
--- a/content/browser/renderer_host/media/audio_input_device_manager.h
+++ b/content/browser/renderer_host/media/audio_input_device_manager.h
@@ -93,6 +93,14 @@ class CONTENT_EXPORT AudioInputDeviceManager : public MediaStreamProvider {
   bool use_fake_device_;
   StreamDeviceList devices_;
 
+#if defined(OS_CHROMEOS)
+  // Flag that's set when we have checked if the system has a keyboard mic. We
+  // only need to check it once, and not when constructing since that will
+  // affect startup time.
+  // Must be accessed on the IO thread;
+  bool has_checked_keyboard_mic_;
+#endif
+
   media::AudioManager* const audio_manager_;  // Weak.
 
   // The message loop of media stream device thread that this object runs on.