[WebViewShell] Add activity for opening urls while creating/destroying webviews.

android_webview/tools/system_webview_shell/apk/src/org/chromium/webview_shell/WebViewCreateDestroyActivity.java

Index: android_webview/tools/system_webview_shell/apk/src/org/chromium/webview_shell/WebViewCreateDestroyActivity.java
diff --git a/android_webview/tools/system_webview_shell/apk/src/org/chromium/webview_shell/WebViewCreateDestroyActivity.java b/android_webview/tools/system_webview_shell/apk/src/org/chromium/webview_shell/WebViewCreateDestroyActivity.java
new file mode 100644
index 0000000000000000000000000000000000000000..6727bbc5051ec12d00ae996e709e19c0791a53c0
--- /dev/null
+++ b/android_webview/tools/system_webview_shell/apk/src/org/chromium/webview_shell/WebViewCreateDestroyActivity.java
@@ -0,0 +1,85 @@
+// Copyright 2016 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.
+
+package org.chromium.webview_shell;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.os.Bundle;
+import android.view.ViewGroup;
+import android.webkit.WebSettings;
+import android.webkit.WebView;
+import android.webkit.WebViewClient;
+import android.widget.RelativeLayout;
+
+/**
+ * This activity always has at most one live webview. Any previously exisisting
+ * webview instance is destroyed first before creating a new one. This activity
+ * is designed for testing create/destroy webview sequence, for catching potential
+ * memory leaks and memory benchmarking.
+ *
+ * Note that this activity does not destroy any webviews in other activities. For
+ * example launching TelemetryActivity followed by WebViewCreateDestroyActivity
+ * will yield two webview instances in total.
+ */
+public class WebViewCreateDestroyActivity extends Activity {
+    private static WebView sWebView;
+
+    @Override
+    protected void onDestroy() {
+        destroyWebViewIfExists();
+        super.onDestroy();
+    }
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_empty);
+        getWindow().setTitle(
+                getResources().getString(R.string.title_activity_create_destroy));
+        onNewIntent(getIntent());
+    }
+
+    @Override
+    protected void onNewIntent(Intent intent) {
+        destroyWebViewIfExists();
+        openUsingNewWebView(intent);
+    }
+
+    private void openUsingNewWebView(Intent intent) {
+        sWebView = new WebView(this);
+        sWebView.setLayoutParams(
+                new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
+                        ViewGroup.LayoutParams.MATCH_PARENT));
+        RelativeLayout layout = (RelativeLayout) findViewById(R.id.emptyview);
+        layout.addView(sWebView);
+
+        WebSettings webSettings = sWebView.getSettings();
+        webSettings.setJavaScriptEnabled(true);
+        webSettings.setUseWideViewPort(true);
+        webSettings.setLoadWithOverviewMode(true);
+
+        sWebView.setWebViewClient(new WebViewClient() {
+                @Override
+                public boolean shouldOverrideUrlLoading(WebView view, String url) {
+                    return false;
+                }
+        });
+
+        String url = getUrlFromIntent(intent);
+        sWebView.loadUrl(url == null ? "about:blank" : url);
+    }
+
+    private void destroyWebViewIfExists() {
+        if (sWebView == null) return;
+        RelativeLayout layout = (RelativeLayout) findViewById(R.id.emptyview);
+        layout.removeView(sWebView);
+        sWebView.destroy();
+        sWebView = null;
+    }
+
+    private static String getUrlFromIntent(Intent intent) {
+        return intent != null ? intent.getDataString() : null;
+    }
+}