Implement MouseEvent buttons attribute.

Source/web/WebInputEventConversion.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 86 matching lines @@
 
     m_modifiers = 0;
     if (e.modifiers & WebInputEvent::ShiftKey)
         m_modifiers |= PlatformEvent::ShiftKey;
     if (e.modifiers & WebInputEvent::ControlKey)
         m_modifiers |= PlatformEvent::CtrlKey;
     if (e.modifiers & WebInputEvent::AltKey)
         m_modifiers |= PlatformEvent::AltKey;
     if (e.modifiers & WebInputEvent::MetaKey)
         m_modifiers |= PlatformEvent::MetaKey;
+    if (e.modifiers & WebInputEvent::LeftButtonDown)
+        m_modifiers |= PlatformEvent::LeftButtonDown;
+    if (e.modifiers & WebInputEvent::MiddleButtonDown)
+        m_modifiers |= PlatformEvent::MiddleButtonDown;
+    if (e.modifiers & WebInputEvent::RightButtonDown)
+        m_modifiers |= PlatformEvent::RightButtonDown;
 
     m_modifierFlags = e.modifiers;
     m_timestamp = e.timeStampSeconds;
     m_clickCount = e.clickCount;
 
+    const unsigned buttonToModifier[] = {
+        PlatformEvent::LeftButtonDown,
+        PlatformEvent::MiddleButtonDown,
+        PlatformEvent::RightButtonDown
+    };
+
     switch (e.type) {
     case WebInputEvent::MouseMove:
     case WebInputEvent::MouseLeave:  // synthesize a move event
         m_type = PlatformEvent::MouseMoved;
         break;
 
     case WebInputEvent::MouseDown:
         m_type = PlatformEvent::MousePressed;
         break;
 
     case WebInputEvent::MouseUp:
         m_type = PlatformEvent::MouseReleased;
+
+        // The MouseEvent spec requires that buttons indicates the state
+        // immediately after the event takes place. To ensure consistency
+        // between platforms here, we explicitly clear the button that is
+        // in the process of being released.
+        m_modifiers &= ~buttonToModifier[e.button];
         break;
 
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
 // PlatformWheelEventBuilder --------------------------------------------------
 
 PlatformWheelEventBuilder::PlatformWheelEventBuilder(Widget* widget, const WebMouseWheelEvent& e)
@@ skipping 11 matching lines @@
 
     m_modifiers = 0;
     if (e.modifiers & WebInputEvent::ShiftKey)
         m_modifiers |= PlatformEvent::ShiftKey;
     if (e.modifiers & WebInputEvent::ControlKey)
         m_modifiers |= PlatformEvent::CtrlKey;
     if (e.modifiers & WebInputEvent::AltKey)
         m_modifiers |= PlatformEvent::AltKey;
     if (e.modifiers & WebInputEvent::MetaKey)
         m_modifiers |= PlatformEvent::MetaKey;
+    if (e.modifiers & WebInputEvent::LeftButtonDown)
+        m_modifiers |= PlatformEvent::LeftButtonDown;
+    if (e.modifiers & WebInputEvent::MiddleButtonDown)
+        m_modifiers |= PlatformEvent::MiddleButtonDown;
+    if (e.modifiers & WebInputEvent::RightButtonDown)
+        m_modifiers |= PlatformEvent::RightButtonDown;
 
     m_hasPreciseScrollingDeltas = e.hasPreciseScrollingDeltas;
 #if OS(MACOSX)
     m_phase = static_cast<PlatformWheelEventPhase>(e.phase);
     m_momentumPhase = static_cast<PlatformWheelEventPhase>(e.momentumPhase);
     m_timestamp = e.timeStampSeconds;
     m_canRubberbandLeft = e.canRubberbandLeft;
     m_canRubberbandRight = e.canRubberbandRight;
 #endif
 }
@@ skipping 651 matching lines @@
     modifiers = getWebInputModifiers(event);
 
     globalX = event.screenX();
     globalY = event.screenY();
     IntPoint localPoint = convertAbsoluteLocationForRenderObject(event.absoluteLocation(), *renderObject);
     x = localPoint.x();
     y = localPoint.y();
 }
 
 } // namespace blink