Add new hotword extension for built-in hotword triggering.

chrome/browser/extensions/external_component_loader.cc

Index: chrome/browser/extensions/external_component_loader.cc
diff --git a/chrome/browser/extensions/external_component_loader.cc b/chrome/browser/extensions/external_component_loader.cc
index 462ea8b6f37860f382984d1ba5639a5c3725a3d8..4520adf19a12d96f2b6eb8da8325b05ab68c9706 100644
--- a/chrome/browser/extensions/external_component_loader.cc
+++ b/chrome/browser/extensions/external_component_loader.cc
@@ -4,6 +4,7 @@
 
 #include "chrome/browser/extensions/external_component_loader.h"
 
+#include "base/command_line.h"
 #include "chrome/browser/bookmarks/enhanced_bookmarks_features.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
@@ -15,6 +16,10 @@
 #include "chrome/browser/search/hotword_service_factory.h"
 #endif
 
+#if defined(OS_CHROMEOS)
+#include "chromeos/chromeos_switches.h"
+#endif
+
 namespace {
 
 bool IsUserSignedin(Profile* profile) {
@@ -41,8 +46,18 @@ void ExternalComponentLoader::StartLoading() {
 #if defined(ENABLE_EXTENSIONS)
   if (HotwordServiceFactory::IsHotwordAllowed(profile_)) {
     std::string hotwordId = extension_misc::kHotwordExtensionId;
-    prefs_->SetString(hotwordId + ".external_update_url",
-                      extension_urls::GetWebstoreUpdateUrl().spec());
+#if defined(OS_CHROMEOS)
+    CommandLine* command_line = CommandLine::ForCurrentProcess();

[James Hawkins, 2014/08/05 08:59:45]

Same as component_loader, create a ChromeOS-specific implementation instead of
using #ifdef.

+    if (command_line->HasSwitch(
+        chromeos::switches::kEnableOkGoogleVoiceSearch)) {
+      // TODO(amistry): Load the hotword shared module.
+      hotwordId = "";
+    }
+#endif
+    if (!hotwordId.empty()) {
+      prefs_->SetString(hotwordId + ".external_update_url",
+                        extension_urls::GetWebstoreUpdateUrl().spec());
+    }
   }
 #endif