The history of webview is not clearing... What is wrong with below code?

Web view Creation

mWebViewReport=(WebView)findViewById(R.id.report_page);
mWebViewReport.setWebViewClient(new HelloWebViewClient());
mWebViewReport.getSettings().setBuiltInZoomControls(true);

Load help file when help button click

mWebViewReport.loadUrl("file:///android_asset/help.html");
mWebViewReport.clearHistory();
mWebViewReport.clearCache(true);

load Summary file when summary button click

  mWebViewReport.loadUrl("file:///android_asset/summary.html");

    //On back button click
     if (mWebViewReport.canGoBack()) {
            mWebViewReport.goBack();
            return ;
      }

Here i can see the Help page too...

android webview android-webview
Edit
Report