Revert r70896 to move speech input back behind a flag.

chrome/browser/speech/speech_input_manager.cc

Index: chrome/browser/speech/speech_input_manager.cc
diff --git a/chrome/browser/speech/speech_input_manager.cc b/chrome/browser/speech/speech_input_manager.cc
index 284a166be1a1df804d90efc57f304175be9a33c8..25f055074bbd4bdaaf948c8b401478f7d555240f 100644
--- a/chrome/browser/speech/speech_input_manager.cc
+++ b/chrome/browser/speech/speech_input_manager.cc
@@ -8,6 +8,7 @@
 #include <string>
 
 #include "app/l10n_util.h"
+#include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/lock.h"
 #include "base/ref_counted.h"
@@ -152,6 +153,26 @@ SpeechInputManager* SpeechInputManager::Get() {
   return g_speech_input_manager_impl.Pointer();
 }
 
+bool SpeechInputManager::IsFeatureEnabled() {
+  bool enabled = true;
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(switches::kDisableSpeechInput)) {
+    enabled = false;
+#if defined(GOOGLE_CHROME_BUILD)
+  } else if (!command_line.HasSwitch(switches::kEnableSpeechInput)) {
+    // We need to evaluate whether IO is OK here. http://crbug.com/63335.
+    base::ThreadRestrictions::ScopedAllowIO allow_io;
+    // Official Chrome builds have speech input enabled by default only in the
+    // dev channel.
+    std::string channel = platform_util::GetVersionStringModifier();
+    enabled = (channel == "dev");
+#endif
+  }
+
+  return enabled;
+}
+
 SpeechInputManagerImpl::SpeechInputManagerImpl()
     : recording_caller_id_(0),
       bubble_controller_(new SpeechInputBubbleController(