Remove the WM_SYSCOMMAND handling from the LegacyRenderWidgetHostHWND class.

content/browser/renderer_host/legacy_render_widget_host_win.cc

Index: content/browser/renderer_host/legacy_render_widget_host_win.cc
diff --git a/content/browser/renderer_host/legacy_render_widget_host_win.cc b/content/browser/renderer_host/legacy_render_widget_host_win.cc
index d0604195f1ce6f7a065bb8246d2c54aa3e481ae9..9c2e1a2e512ccf646dec9ce48388b4e5b44a3e6b 100644
--- a/content/browser/renderer_host/legacy_render_widget_host_win.cc
+++ b/content/browser/renderer_host/legacy_render_widget_host_win.cc
@@ -224,6 +224,15 @@ LRESULT LegacyRenderWidgetHostHWND::OnMouseRange(UINT message,
     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;
 }
@@ -362,18 +371,4 @@ LRESULT LegacyRenderWidgetHostHWND::OnSize(UINT message,
   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