Merge "Dump log instead of throwing exception" into main

                // registration in DisplayContent#onParentChanged at DisplayContent initialization.

                final DisplayContent dc = mRoot.getDisplayContent(displayId);

                if (dc == null) {

                    if (callingPid != MY_PID) {

                        throw new IllegalArgumentException(

                                "attachWindowContextToDisplayContent: trying to attach to a"

                                        + " non-existing display:" + displayId);

                    }

                    // Early return if this method is invoked from system process.

                    // See above comments for more detail.

                    ProtoLog.w(WM_ERROR, "attachWindowContextToDisplayContent: trying"

                            + " to attach to a non-existing display:" + displayId);

                    return null;

                }

                mWindowContextListenerController.registerWindowContainerListener(wpc, clientToken,