Fixed drag and drop into and out of Browser Plugin.

chrome/test/base/ui_controls_aurax11.cc

Index: chrome/test/base/ui_controls_aurax11.cc
diff --git a/chrome/test/base/ui_controls_aurax11.cc b/chrome/test/base/ui_controls_aurax11.cc
index 9d57fbc9b5c8b37f4d0d8013823875ff32747b4d..7e914e32c06015d4c4ff7a6aa88d12d8ec6b1ed5 100644
--- a/chrome/test/base/ui_controls_aurax11.cc
+++ b/chrome/test/base/ui_controls_aurax11.cc
@@ -166,30 +166,35 @@ class UIControlsX11 : public UIControlsAura {
     xbutton->x = mouse_loc.x();
     xbutton->y = mouse_loc.y();
     xbutton->same_screen = True;
+    // According to http://tronche.com/gui/x/xlib/events/keyboard-pointer/
+    //    keyboard-pointer.html#XButtonEvent, the state should be set to the
+    // button state just prior to the event.
+    xbutton->state = button_down_mask;
+    unsigned button = 0;
     switch (type) {
       case LEFT:
         xbutton->button = Button1;
-        xbutton->state = Button1Mask;
+        button = Button1Mask;
         break;
       case MIDDLE:
         xbutton->button = Button2;
-        xbutton->state = Button2Mask;
+        button = Button2Mask;
         break;
       case RIGHT:
         xbutton->button = Button3;
-        xbutton->state = Button3Mask;
+        button = Button3Mask;
         break;
     }
     // RootWindow will take care of other necessary fields.
     if (state & DOWN) {
       xevent.xbutton.type = ButtonPress;
       root_window_->PostNativeEvent(&xevent);
-      button_down_mask |= xbutton->state;
+      button_down_mask |= button;
     }
     if (state & UP) {
       xevent.xbutton.type = ButtonRelease;
       root_window_->PostNativeEvent(&xevent);
-      button_down_mask = (button_down_mask | xbutton->state) ^ xbutton->state;
+      button_down_mask &= ~button;
     }
     RunClosureAfterAllPendingUIEvents(closure);
     return true;