Support multi-button press for synthetic mouse events

content/browser/renderer_host/input/synthetic_mouse_driver.cc

Index: content/browser/renderer_host/input/synthetic_mouse_driver.cc
diff --git a/content/browser/renderer_host/input/synthetic_mouse_driver.cc b/content/browser/renderer_host/input/synthetic_mouse_driver.cc
index 4db6f2deaf3639571e59d6217f89616b6047b38f..bc3537afc8b8dea677f3e3a4f9b438ac4327d64d 100644
--- a/content/browser/renderer_host/input/synthetic_mouse_driver.cc
+++ b/content/browser/renderer_host/input/synthetic_mouse_driver.cc
@@ -8,7 +8,7 @@
 
 namespace content {
 
-SyntheticMouseDriver::SyntheticMouseDriver() {}
+SyntheticMouseDriver::SyntheticMouseDriver() : last_modifiers_(0) {}
 
 SyntheticMouseDriver::~SyntheticMouseDriver() {}
 
@@ -18,11 +18,19 @@ void SyntheticMouseDriver::DispatchEvent(SyntheticGestureTarget* target,
   target->DispatchInputEventToPlatform(mouse_event_);
 }
 
-void SyntheticMouseDriver::Press(float x, float y, int index) {
+void SyntheticMouseDriver::Press(float x,
+                                 float y,
+                                 int index,
+                                 SyntheticPointerActionParams::Button button) {
   DCHECK_EQ(index, 0);
+  int modifiers =
+      SyntheticPointerActionParams::GetWebMouseEventModifier(button);
   mouse_event_ = SyntheticWebMouseEventBuilder::Build(
-      blink::WebInputEvent::MouseDown, x, y, 0);
+      blink::WebInputEvent::MouseDown, x, y, modifiers | last_modifiers_);
   mouse_event_.clickCount = 1;
+  mouse_event_.button =
+      SyntheticPointerActionParams::GetWebMouseEventButton(button);
+  last_modifiers_ = modifiers | last_modifiers_;
 }
 
 void SyntheticMouseDriver::Move(float x, float y, int index) {
@@ -30,16 +38,24 @@ void SyntheticMouseDriver::Move(float x, float y, int index) {
   blink::WebMouseEvent::Button button = mouse_event_.button;
   int click_count = mouse_event_.clickCount;
   mouse_event_ = SyntheticWebMouseEventBuilder::Build(
-      blink::WebInputEvent::MouseMove, x, y, 0);
+      blink::WebInputEvent::MouseMove, x, y, last_modifiers_);
   mouse_event_.button = button;
   mouse_event_.clickCount = click_count;
 }
 
-void SyntheticMouseDriver::Release(int index) {
+void SyntheticMouseDriver::Release(
+    int index,
+    SyntheticPointerActionParams::Button button) {
   DCHECK_EQ(index, 0);
   mouse_event_ = SyntheticWebMouseEventBuilder::Build(
-      blink::WebInputEvent::MouseUp, mouse_event_.x, mouse_event_.y, 0);
+      blink::WebInputEvent::MouseUp, mouse_event_.x, mouse_event_.y,
+      last_modifiers_);
   mouse_event_.clickCount = 1;
+  mouse_event_.button =
+      SyntheticPointerActionParams::GetWebMouseEventButton(button);
+  last_modifiers_ =
+      last_modifiers_ &
+      (~SyntheticPointerActionParams::GetWebMouseEventModifier(button));
 }
 
 bool SyntheticMouseDriver::UserInputCheck(
@@ -53,9 +69,11 @@ bool SyntheticMouseDriver::UserInputCheck(
   }
 
   if (params.pointer_action_type() ==
-          SyntheticPointerActionParams::PointerActionType::PRESS &&
-      mouse_event_.clickCount > 0) {
-    return false;
+      SyntheticPointerActionParams::PointerActionType::PRESS) {
+    int modifiers =
+        SyntheticPointerActionParams::GetWebMouseEventModifier(params.button());
+    if (last_modifiers_ & modifiers)
+      return false;
   }
 
   if (params.pointer_action_type() ==