input: Remove dead code.

content/browser/renderer_host/input/synthetic_gesture_controller.h

Index: content/browser/renderer_host/input/synthetic_gesture_controller.h
diff --git a/content/browser/renderer_host/input/synthetic_gesture_controller.h b/content/browser/renderer_host/input/synthetic_gesture_controller.h
index 280c077b8529b42ef119c9cdf2c24397034f0857..5ed093af69451fccdd50a2d0a6bea17326ded4fe 100644
--- a/content/browser/renderer_host/input/synthetic_gesture_controller.h
+++ b/content/browser/renderer_host/input/synthetic_gesture_controller.h
@@ -32,11 +32,6 @@ class CONTENT_EXPORT SyntheticGestureController {
    public:
     virtual ~Delegate() {}
 
-    // Requests a single begin frame. The passed callback is run on the next
-    // begin frame message.
-    virtual void RequestBeginFrameForSynthesizedInput(
-        base::OnceClosure callback) = 0;
-
     // Returns whether any gesture created by dispatched input events has
     // completed or not.
     virtual bool HasGestureStopped() = 0;