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..445027c4aed1633375e230e7ace2abeb967184e9 100644
--- a/content/browser/renderer_host/input/synthetic_mouse_driver.cc
+++ b/content/browser/renderer_host/input/synthetic_mouse_driver.cc
@@ -8,7 +8,36 @@
 
 namespace content {
 
-SyntheticMouseDriver::SyntheticMouseDriver() {}
+namespace {
+
+unsigned GetWebMouseEventModifier(int button) {
+  switch (button) {
+    case 0:
+      return blink::WebMouseEvent::LeftButtonDown;
+    case 1:
+      return blink::WebMouseEvent::MiddleButtonDown;
+    case 2:
+      return blink::WebMouseEvent::RightButtonDown;
+  }
+  NOTREACHED();
+  return blink::WebMouseEvent::NoModifiers;
+}
+
+blink::WebMouseEvent::Button GetWebMouseEventButton(int button) {
+  switch (button) {
+    case 0:
+      return blink::WebMouseEvent::Button::Left;
+    case 1:
+      return blink::WebMouseEvent::Button::Middle;
+    case 2:
+      return blink::WebMouseEvent::Button::Right;
+  }
+  NOTREACHED();
+  return blink::WebMouseEvent::Button::NoButton;
+}
+}
+
+SyntheticMouseDriver::SyntheticMouseDriver() : last_modifiers_(0) {}
 
 SyntheticMouseDriver::~SyntheticMouseDriver() {}
 
@@ -18,11 +47,14 @@ 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, int button) {
   DCHECK_EQ(index, 0);
+  int modifiers = 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 = GetWebMouseEventButton(button);
+  last_modifiers_ = modifiers | last_modifiers_;
 }
 
 void SyntheticMouseDriver::Move(float x, float y, int index) {
@@ -30,16 +62,19 @@ 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, int 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 = GetWebMouseEventButton(button);
+  last_modifiers_ = last_modifiers_ & (~GetWebMouseEventModifier(button));
 }
 
 bool SyntheticMouseDriver::UserInputCheck(
@@ -53,9 +88,10 @@ bool SyntheticMouseDriver::UserInputCheck(
   }
 
   if (params.pointer_action_type() ==
-          SyntheticPointerActionParams::PointerActionType::PRESS &&
-      mouse_event_.clickCount > 0) {
-    return false;
+      SyntheticPointerActionParams::PointerActionType::PRESS) {
+    int modifiers = GetWebMouseEventModifier(params.button());
+    if (last_modifiers_ & modifiers)
+      return false;
   }
 
   if (params.pointer_action_type() ==