Support multi-button press for synthetic mouse events

content/browser/renderer_host/input/synthetic_touch_driver.h

Index: content/browser/renderer_host/input/synthetic_touch_driver.h
diff --git a/content/browser/renderer_host/input/synthetic_touch_driver.h b/content/browser/renderer_host/input/synthetic_touch_driver.h
index 71d9674c3daba1b874290b2f609704dd17363ca5..9fea5fdcd79507fbe3f6fe21bd4e88b2613c6ed3 100644
--- a/content/browser/renderer_host/input/synthetic_touch_driver.h
+++ b/content/browser/renderer_host/input/synthetic_touch_driver.h
@@ -22,9 +22,9 @@ class CONTENT_EXPORT SyntheticTouchDriver : public SyntheticPointerDriver {
   void DispatchEvent(SyntheticGestureTarget* target,
                      const base::TimeTicks& timestamp) override;
 
-  void Press(float x, float y, int index) override;
+  void Press(float x, float y, int index, int button = 0) override;
   void Move(float x, float y, int index) override;
-  void Release(int index) override;
+  void Release(int index, int button = 0) override;
 
   bool UserInputCheck(
       const SyntheticPointerActionParams& params) const override;