Allow virtual keyboard window to access audio stream and speech api for voice input

ui/keyboard/keyboard_controller_proxy.h

Index: ui/keyboard/keyboard_controller_proxy.h
diff --git a/ui/keyboard/keyboard_controller_proxy.h b/ui/keyboard/keyboard_controller_proxy.h
index 09e88cdbeeb431db06f4457f78c1cd371c472d38..e88e52b60050274f1775a1d754783f7f875d980f 100644
--- a/ui/keyboard/keyboard_controller_proxy.h
+++ b/ui/keyboard/keyboard_controller_proxy.h
@@ -6,6 +6,7 @@
 #define UI_KEYBOARD_KEYBOARD_CONTROLLER_PROXY_H_
 
 #include "base/memory/scoped_ptr.h"
+#include "content/public/common/media_stream_request.h"
 #include "ui/keyboard/keyboard_export.h"
 
 namespace aura {
@@ -40,6 +41,11 @@ class KEYBOARD_EXPORT KeyboardControllerProxy {
   // text input context.
   virtual ui::InputMethod* GetInputMethod() = 0;
 
+  // Requests the audio input from microphone for speech input.
+  virtual void RequestAudioInput(content::WebContents* web_contents,
+      const content::MediaStreamRequest& request,
+      const content::MediaResponseCallback& callback) = 0;
+
   // Shows the container window of the keyboard. The default implementation
   // simply shows the container. An overridden implementation can set up
   // necessary animation, or delay the visibility change as it desires.