Android 4.4 系统开机会弹出Android 正在检查文件系统...

代码路径：
frameworks/base/core/res/res/values-zh-rCN/strings.xml
frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
在strings.xml文件中有该字段android_checking_file_system_title

"Android 正在检查文件系统..."

在PhoneWindowManager.java文件中showBootMessage()方法中isNormal字段表示是否是正常开机启动，如果是异常开机启动就会弹出该对话框 " Android 正在检查文件系统…"

public void showBootMessage(final CharSequence msg, final boolean always) {
        if (mHeadless) return;
        mHandler.post(new Runnable() {
            @Override public void run() {
                if (mBootMsgDialog == null) {
                    mBootMsgDialog = new ProgressDialog(mContext) {
                        // This dialog will consume all events coming in to
                        // it, to avoid it trying to do things too early in boot.
                        @Override public boolean dispatchKeyEvent(KeyEvent event) {
                            return true;
                        }
                        @Override public boolean dispatchKeyShortcutEvent(KeyEvent event) {
                            return true;
                        }
                        @Override public boolean dispatchTouchEvent(MotionEvent ev) {
                            return true;
                        }
                        @Override public boolean dispatchTrackballEvent(MotionEvent ev) {
                            return true;
                        }
                        @Override public boolean dispatchGenericMotionEvent(MotionEvent ev) {
                            return true;
                        }
                        @Override public boolean dispatchPopulateAccessibilityEvent(
                                AccessibilityEvent event) {
                            return true;
                        }
                    };
                    
                    //mBootMsgDialog.setTitle(R.string.android_upgrading_title);
                    boolean isNormal = SystemProperties.get("persist.sys.lastbootflagbak", "unnormal").equals("normal");
                    mBootMsgDialog.setTitle(isNormal?R.string.android_upgrading_title:
                                           R.string.android_checking_file_system_title);
                    
                    mBootMsgDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
                    mBootMsgDialog.setIndeterminate(true);
                    mBootMsgDialog.getWindow().setType(
                            WindowManager.LayoutParams.TYPE_BOOT_PROGRESS);
                    mBootMsgDialog.getWindow().addFlags(
                            WindowManager.LayoutParams.FLAG_DIM_BEHIND
                            | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);
                    mBootMsgDialog.getWindow().setDimAmount(1);
                    WindowManager.LayoutParams lp = mBootMsgDialog.getWindow().getAttributes();
                    lp.screenOrientation = ActivityInfo.SCREEN_ORIENTATION_NOSENSOR;
                    mBootMsgDialog.getWindow().setAttributes(lp);
                    mBootMsgDialog.setCancelable(false);
                    mBootMsgDialog.show();
                }
                mBootMsgDialog.setMessage(msg);
            }
        });
    }