Support multi-button press for synthetic mouse events

content/browser/renderer_host/input/synthetic_touch_driver.cc

Index: content/browser/renderer_host/input/synthetic_touch_driver.cc
diff --git a/content/browser/renderer_host/input/synthetic_touch_driver.cc b/content/browser/renderer_host/input/synthetic_touch_driver.cc
index 3adb753c6162b1c65e3a2d338e5aaad29ff77849..5d3a8769b68e7136cbe05a79221283beaa81a9d3 100644
--- a/content/browser/renderer_host/input/synthetic_touch_driver.cc
+++ b/content/browser/renderer_host/input/synthetic_touch_driver.cc
@@ -22,11 +22,12 @@ SyntheticTouchDriver::~SyntheticTouchDriver() {}
 void SyntheticTouchDriver::DispatchEvent(SyntheticGestureTarget* target,
                                          const base::TimeTicks& timestamp) {
   touch_event_.setTimeStampSeconds(ConvertTimestampToSeconds(timestamp));
-  target->DispatchInputEventToPlatform(touch_event_);
+  if (touch_event_.type() != blink::WebInputEvent::Undefined)
+    target->DispatchInputEventToPlatform(touch_event_);
   touch_event_.ResetPoints();
 }
 
-void SyntheticTouchDriver::Press(float x, float y, int index) {
+void SyntheticTouchDriver::Press(float x, float y, int index, int button) {
   DCHECK_GE(index, 0);
   DCHECK_LT(index, blink::WebTouchEvent::kTouchesLengthCap);
   int touch_index = touch_event_.PressPoint(x, y);
@@ -39,7 +40,7 @@ void SyntheticTouchDriver::Move(float x, float y, int index) {
   touch_event_.MovePoint(index_map_[index], x, y);
 }
 
-void SyntheticTouchDriver::Release(int index) {
+void SyntheticTouchDriver::Release(int index, int button) {
   DCHECK_GE(index, 0);
   DCHECK_LT(index, blink::WebTouchEvent::kTouchesLengthCap);
   touch_event_.ReleasePoint(index_map_[index]);