Fixed drag and drop into and out of Browser Plugin.

chrome/test/base/ui_controls_aurax11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
 
 // X macro fail.
 #if defined(RootWindow)
 #undef RootWindow
@@ skipping 148 matching lines @@
     XEvent xevent = {0};
     XButtonEvent* xbutton = &xevent.xbutton;
     gfx::Point mouse_loc = aura::Env::GetInstance()->last_mouse_location();
     aura::client::ScreenPositionClient* screen_position_client =
           aura::client::GetScreenPositionClient(root_window_);
     if (screen_position_client)
       screen_position_client->ConvertPointFromScreen(root_window_, &mouse_loc);
     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/

[dcheng, 2013/04/18 21:10:34]

Nit: Just looking at the diff, it's not 100% clear why this change was needed.
Presumably it was a bug fix of some sort, but for future patches, it'd be nice
to break this part of the patch out and land it separately.

+    //    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;
   }
   virtual bool SendMouseClick(MouseButton type) OVERRIDE {
     return SendMouseEvents(type, UP | DOWN);
   }
   virtual void RunClosureAfterAllPendingUIEvents(
       const base::Closure& closure) OVERRIDE {
     if (closure.is_null())
@@ skipping 36 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(UIControlsX11);
 };
 
 }  // namespace
 
 UIControlsAura* CreateUIControlsAura(aura::RootWindow* root_window) {
   return new UIControlsX11(root_window);
 }
 
 }  // namespace ui_controls