[Hotword] Implement IsHotwordHardwareAvailable() using device types.

chrome/browser/search/hotword_service.cc

Index: chrome/browser/search/hotword_service.cc
diff --git a/chrome/browser/search/hotword_service.cc b/chrome/browser/search/hotword_service.cc
index b6b54ae69801b69b13e63629bc72266f4399512f..b7d16f132964c43cd9f783358342c6cb8d677267 100644
--- a/chrome/browser/search/hotword_service.cc
+++ b/chrome/browser/search/hotword_service.cc
@@ -49,6 +49,10 @@
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/audio/cras_audio_handler.h"
+#endif
+
 using extensions::BrowserContextKeyedAPIFactory;
 using extensions::HotwordPrivateEventService;
 
@@ -307,6 +311,13 @@ HotwordService::HotwordService(Profile* profile)
       reinstall_pending_(false),
       training_(false),
       weak_factory_(this) {
+#if defined(OS_CHROMEOS)
+  // Tests on chromeos need to have the handler initialized.
+  if (profile_->AsTestingProfile() &&
+      !chromeos::CrasAudioHandler::IsInitialized())
+    chromeos::CrasAudioHandler::InitializeForTesting();
+#endif
+
   extension_registry_observer_.Add(extensions::ExtensionRegistry::Get(profile));
   if (IsExperimentalHotwordingEnabled()) {
     // Disable the old extension so it doesn't interfere with the new stuff.