Remove the WM_SYSCOMMAND handling from the LegacyRenderWidgetHostHWND class.

content/browser/renderer_host/legacy_render_widget_host_win.cc

 // Copyright (c) 2014 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 "content/browser/renderer_host/legacy_render_widget_host_win.h"
 
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/win/windows_version.h"
 #include "content/browser/accessibility/browser_accessibility_manager_win.h"
@@ skipping 206 matching lines @@
     l_param = MAKELPARAM(mouse_coords.x, mouse_coords.y);
   }
 
   LRESULT ret = 0;
 
   if (GetWindowEventTarget(GetParent())) {
     bool msg_handled = false;
     ret = GetWindowEventTarget(GetParent())->HandleMouseMessage(
         message, w_param, l_param, &msg_handled);
     handled = msg_handled;
+    // If the parent did not handle non client mouse messages, we call
+    // DefWindowProc on the message with the parent window handle. This
+    // ensures that WM_SYSCOMMAND is generated for the parent and we are
+    // out of the picture.
+    if (!handled &&
+         (message >= WM_NCMOUSEMOVE && message <= WM_NCXBUTTONDBLCLK)) {
+      ret = ::DefWindowProc(GetParent(), message, w_param, l_param);
+      handled = TRUE;
+    }
   }
   return ret;
 }
 
 LRESULT LegacyRenderWidgetHostHWND::OnMouseLeave(UINT message,
                                                  WPARAM w_param,
                                                  LPARAM l_param) {
   mouse_tracking_enabled_ = false;
   LRESULT ret = 0;
   if ((::GetCapture() != GetParent()) && GetWindowEventTarget(GetParent())) {
@@ skipping 118 matching lines @@
   // Additionally others check if the window WS_VSCROLL/WS_HSCROLL styles and
   // generate the legacy WM_VSCROLL/WM_HSCROLL messages.
   // We add these styles to ensure that trackpad/trackpoint scrolling
   // work.
   long current_style = ::GetWindowLong(hwnd(), GWL_STYLE);
   ::SetWindowLong(hwnd(), GWL_STYLE,
                   current_style | WS_VSCROLL | WS_HSCROLL);
   return 0;
 }
 
-LRESULT LegacyRenderWidgetHostHWND::OnSysCommand(UINT message,
-                                                 WPARAM w_param,
-                                                 LPARAM l_param) {
-  LRESULT ret = 0;
-  if (GetWindowEventTarget(GetParent())) {
-    bool msg_handled = false;
-    ret = GetWindowEventTarget(
-        GetParent())->HandleSysCommand(message, w_param, l_param,
-                                       &msg_handled);
-    SetMsgHandled(msg_handled);
-  }
-  return ret;
-}
-
 }  // namespace content