Adds the audio history and always on hotwording settings.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 96a76c0a5f4a221366438407e1399b81f24c2891..82e55106d6179e1844cf8a1482ea68cc3179a7be 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1778,6 +1778,10 @@ const char kVideoCaptureAllowedUrls[] = "hardware.video_capture_allowed_urls";
 // trigger.
 const char kHotwordSearchEnabled[] = "hotword.search_enabled_2";
 
+// A boolean pref that controls the enabled-state of hotword search voice
+// trigger from any screen.
+const char kHotwordAlwaysOnSearchEnabled[] = "hotword.always_on_search_enabled";

[Matt Giuca, 2014/08/12 08:37:39]

This needs to be in OS_CHROMEOS only (doesn't compile on non-CrOS build). You
should move it to just before kConsumerManagementEnrollmentState, so it matches
the order in pref_names.h.

Alternatively, maybe this pref's existence should not be guarded by OS_CHROMEOS.
Rather, just ignore it if OS_CHROMEOS is false (so that we have the possibility
of enabling it later). Either way, make sure the .h and .cc files give things in
the same order.

[Anand Mistry (off Chromium), 2014/08/12 08:46:35]

Please don't guard this with OS_CHROMEOS. It should work on regular chrome as
well.

[rpetterson, 2014/08/12 18:21:57]

+1 My understanding is that although we'll be launching on ChromeOS this will be
a feature available to power users on Chrome.

[kcarattini, 2014/08/13 03:51:54]

Done. Sorry, everyone! Leftover from before I merged with Anand's change that
moved the flag out of ChromeOS.

+
 // A boolean pref that controls whether the sound of "Ok, Google" plus a few
 // seconds of audio data before is sent back to improve voice search.
 const char kHotwordAudioLoggingEnabled[] = "hotword.audio_logging_enabled";