Implement MouseEvent buttons attribute.

Source/core/page/EventHandler.cpp

Index: Source/core/page/EventHandler.cpp
diff --git a/Source/core/page/EventHandler.cpp b/Source/core/page/EventHandler.cpp
index b494da3325acd28ce3d7869fbb6448eaecd65c29..b842cc12f52404bec620b021f34568b2bab3636b 100644
--- a/Source/core/page/EventHandler.cpp
+++ b/Source/core/page/EventHandler.cpp
@@ -1634,12 +1634,14 @@ bool EventHandler::dispatchDragEvent(const AtomicString& eventType, Node* dragTa
     if (!view)
         return false;
 
+    // FIXME: The drag event have to support for |buttons| attribute because
+    // the event is derived from mouse event. Please see crbug.com/276941.
     RefPtrWillBeRawPtr<MouseEvent> me = MouseEvent::create(eventType,
         true, true, m_frame->document()->domWindow(),
         0, event.globalPosition().x(), event.globalPosition().y(), event.position().x(), event.position().y(),
         event.movementDelta().x(), event.movementDelta().y(),
         event.ctrlKey(), event.altKey(), event.shiftKey(), event.metaKey(),
-        0, nullptr, dataTransfer);
+        0, 0, nullptr, dataTransfer);
 
     dragTarget->dispatchEvent(me.get(), IGNORE_EXCEPTION);
     return me->defaultPrevented();
@@ -2224,6 +2226,27 @@ bool EventHandler::handleGestureScrollEvent(const PlatformGestureEvent& gestureE
     }
 }
 
+static PlatformEvent::Modifiers platformModifiersFrom(unsigned modifierFlags)

[Rick Byers, 2014/11/28 17:36:02]

nit: this function is simple enough you should just write the cast inline rather
than use a helper function.

[zino, 2014/12/03 15:47:15]

Done.

+{
+    return static_cast<PlatformEvent::Modifiers>(modifierFlags);
+}
+
+static unsigned modifierFlagsFrom(const PlatformGestureEvent& event)

[Rick Byers, 2014/11/28 17:36:02]

Isn't this function pretty much equivalent to just 'return event.modifiers()'? 
You should just be able to copy the modifiers directly without needing this
function at all, right?  I'm not sure why the original code was doing this -
maybe just old...

[zino, 2014/12/03 15:47:15]

Yep.. you're right :)
Thanks.

Done.

+{
+    unsigned modifierFlags = 0;
+
+    if (event.altKey())
+        modifierFlags |= PlatformEvent::AltKey;
+    if (event.ctrlKey())
+        modifierFlags |= PlatformEvent::CtrlKey;
+    if (event.metaKey())
+        modifierFlags |= PlatformEvent::MetaKey;
+    if (event.shiftKey())
+        modifierFlags |= PlatformEvent::ShiftKey;
+
+    return modifierFlags;
+}
+
 bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& targetedEvent)
 {
     RefPtrWillBeRawPtr<FrameView> protector(m_frame->view());
@@ -2232,16 +2255,7 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
 
     UserGestureIndicator gestureIndicator(DefinitelyProcessingUserGesture);
 
-    unsigned modifierFlags = 0;
-    if (gestureEvent.altKey())
-        modifierFlags |= PlatformEvent::AltKey;
-    if (gestureEvent.ctrlKey())
-        modifierFlags |= PlatformEvent::CtrlKey;
-    if (gestureEvent.metaKey())
-        modifierFlags |= PlatformEvent::MetaKey;
-    if (gestureEvent.shiftKey())
-        modifierFlags |= PlatformEvent::ShiftKey;
-    PlatformEvent::Modifiers modifiers = static_cast<PlatformEvent::Modifiers>(modifierFlags);
+    unsigned modifierFlags = modifierFlagsFrom(gestureEvent);
 
     HitTestResult currentHitTest = targetedEvent.hitTestResult();
 
@@ -2251,7 +2265,8 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
 
     PlatformMouseEvent fakeMouseMove(gestureEvent.position(), gestureEvent.globalPosition(),
         NoButton, PlatformEvent::MouseMoved, /* clickCount */ 0,
-        modifiers, PlatformMouseEvent::FromTouch, gestureEvent.timestamp());
+        platformModifiersFrom(modifierFlags),
+        PlatformMouseEvent::FromTouch, gestureEvent.timestamp());
     dispatchMouseEvent(EventTypeNames::mousemove, currentHitTest.innerNode(), 0, fakeMouseMove, true);
 
     // Do a new hit-test in case the mousemove event changed the DOM.
@@ -2267,7 +2282,8 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
 
     PlatformMouseEvent fakeMouseDown(gestureEvent.position(), gestureEvent.globalPosition(),
         LeftButton, PlatformEvent::MousePressed, gestureEvent.tapCount(),
-        modifiers, PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
+        platformModifiersFrom(modifierFlags | PlatformEvent::LeftButtonDown),
+        PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
     bool swallowMouseDownEvent = !dispatchMouseEvent(EventTypeNames::mousedown, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseDown, true);
     if (!swallowMouseDownEvent)
         swallowMouseDownEvent = handleMouseFocus(MouseEventWithHitTestResults(fakeMouseDown, currentHitTest));
@@ -2282,7 +2298,8 @@ bool EventHandler::handleGestureTap(const GestureEventWithHitTestResults& target
         currentHitTest = hitTestResultInFrame(m_frame, adjustedPoint, hitType);
     PlatformMouseEvent fakeMouseUp(gestureEvent.position(), gestureEvent.globalPosition(),
         LeftButton, PlatformEvent::MouseReleased, gestureEvent.tapCount(),
-        modifiers, PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
+        platformModifiersFrom(modifierFlags),
+        PlatformMouseEvent::FromTouch,  gestureEvent.timestamp());
     bool swallowMouseUpEvent = !dispatchMouseEvent(EventTypeNames::mouseup, currentHitTest.innerNode(), gestureEvent.tapCount(), fakeMouseUp, false);
 
     bool swallowClickEvent = false;
@@ -2311,6 +2328,8 @@ bool EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults&
     const PlatformGestureEvent& gestureEvent = targetedEvent.event();
     IntPoint adjustedPoint = gestureEvent.position();
 
+    unsigned modifierFlags = modifierFlagsFrom(gestureEvent);
+
     // FIXME: Ideally we should try to remove the extra mouse-specific hit-tests here (re-using the
     // supplied HitTestResult), but that will require some overhaul of the touch drag-and-drop code
     // and LongPress is such a special scenario that it's unlikely to matter much in practice.
@@ -2318,11 +2337,13 @@ bool EventHandler::handleGestureLongPress(const GestureEventWithHitTestResults&
     m_longTapShouldInvokeContextMenu = false;
     if (m_frame->settings() && m_frame->settings()->touchDragDropEnabled() && m_frame->view()) {
         PlatformMouseEvent mouseDownEvent(adjustedPoint, gestureEvent.globalPosition(), LeftButton, PlatformEvent::MousePressed, 1,
-            gestureEvent.shiftKey(), gestureEvent.ctrlKey(), gestureEvent.altKey(), gestureEvent.metaKey(), PlatformMouseEvent::FromTouch, WTF::currentTime());
+            platformModifiersFrom(modifierFlags | PlatformEvent::LeftButtonDown),
+            PlatformMouseEvent::FromTouch, WTF::currentTime());
         m_mouseDown = mouseDownEvent;
 
         PlatformMouseEvent mouseDragEvent(adjustedPoint, gestureEvent.globalPosition(), LeftButton, PlatformEvent::MouseMoved, 1,
-            gestureEvent.shiftKey(), gestureEvent.ctrlKey(), gestureEvent.altKey(), gestureEvent.metaKey(), PlatformMouseEvent::FromTouch, WTF::currentTime());
+            platformModifiersFrom(modifierFlags | PlatformEvent::LeftButtonDown),
+            PlatformMouseEvent::FromTouch, WTF::currentTime());
         HitTestRequest request(HitTestRequest::ReadOnly);
         MouseEventWithHitTestResults mev = prepareMouseEvent(request, mouseDragEvent);
         m_mouseDownMayStartDrag = true;
@@ -2834,7 +2855,9 @@ bool EventHandler::sendContextMenuEventForGesture(const GestureEventWithHitTestR
     PlatformEvent::Type eventType = PlatformEvent::MousePressed;

[Rick Byers, 2014/11/28 17:36:02]

Looks like I was wrong and this OS behavior difference will effect your CL for
the gesture long tap case only.  You need to add RightButtonDown to the
modifiers for the MousePressed (non-windows) case.

Sadly I guess this means you'll need a platform-specific expectations file for
windows (and need to detect windows from your layout test to change your
expected button for this case).  Really the right fix here is to add a
WebPreference for 'show contextmenu on mouseup' which chrome sets to true only
on Windows (then we could test both in the same layout tests on all platforms). 
This might be a nice follow-up CL if you're interested.  If you want to do this,
then feel free to disable the test on Windows for now against that bug (or
better - just land an expectation that has a FAIL in it), rather than trying to
detect Windows and making it pass cleanly...

[zino, 2014/12/03 15:47:15]

Thank you for your guide.
As you know, these works are in review.

 #endif
 
-    PlatformMouseEvent mouseEvent(targetedEvent.event().position(), targetedEvent.event().globalPosition(), RightButton, eventType, 1, false, false, false, false, PlatformMouseEvent::FromTouch, WTF::currentTime());
+    PlatformMouseEvent mouseEvent(targetedEvent.event().position(), targetedEvent.event().globalPosition(), RightButton, eventType, 1,
+        platformModifiersFrom(modifierFlagsFrom(targetedEvent.event())),
+        PlatformMouseEvent::FromTouch, WTF::currentTime());
     // To simulate right-click behavior, we send a right mouse down and then
     // context menu event.
     // FIXME: Send HitTestResults to avoid redundant hit tests.