Revert of Remove setVoiceSearchSupported part of EmbeddedSearch SearchBox API.

chrome/browser/ui/browser_commands.cc

Index: chrome/browser/ui/browser_commands.cc
diff --git a/chrome/browser/ui/browser_commands.cc b/chrome/browser/ui/browser_commands.cc
index 8b7e06b7793dcbcbc832c61c882221cc160a5e3d..12f21b3084b62654b2367e199b06eecc95a17cfc 100644
--- a/chrome/browser/ui/browser_commands.cc
+++ b/chrome/browser/ui/browser_commands.cc
@@ -1131,6 +1131,15 @@
   }
 }
 
+void ToggleSpeechInput(Browser* browser) {
+  SearchTabHelper* search_tab_helper =
+      SearchTabHelper::FromWebContents(
+          browser->tab_strip_model()->GetActiveWebContents());
+  // |search_tab_helper| can be null in unit tests.
+  if (search_tab_helper)
+    search_tab_helper->ToggleVoiceSearch();
+}
+
 void DistillCurrentPage(Browser* browser) {
   DistillCurrentPageAndView(browser->tab_strip_model()->GetActiveWebContents());
 }