Webxdc fixes (#2458)

This now fixes all the checks in the `test webxdc`, see the
Delta Chat group

res/raw/webxdc_wrapper.html

@@ -0,0 +1,107 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+      html,
+      body {
+        margin: 0;
+        padding: 0;
+      }
+      .iframe-container {
+        overflow: hidden;
+        height: 100vh;
+        width: 100vw;
+        position: relative;
+      }
+      .iframe-container iframe {
+        border: 0;
+        height: 100%;
+        left: 0;
+        position: absolute;
+        top: 0;
+        width: 100%;
+      }
+      #progress {
+        width: 100%;
+      }
+    </style>
+  </head>
+  <body>
+    <div id="loading">
+      <progress id="progress" max="100" value="0"></progress>
+    </div>
+    <div class="iframe-container">
+      <iframe id="frame"></iframe>
+    </div>
+    <iframe id="test-isolated-sandbox-context" style="display: none"></iframe>
+    <script>
+      const thisUnchangable = (async () => {
+        const connections = [];
+        const loadingProgress = document.getElementById("progress");
+        const loadingDiv = document.getElementById("loading");
+        const iframe = document.getElementById("frame");
+        const isolatedContextTest = document.getElementById(
+          "test-isolated-sandbox-context"
+        );
+
+        const cert = {
+          certificates: [
+            await RTCPeerConnection.generateCertificate({
+              name: "ECDSA",
+              namedCurve: "P-256",
+            }),
+          ],
+        };
+
+        try {
+          for (let i = 0; i < 50; i++) {
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            connections.push(new RTCPeerConnection(cert));
+            loadingProgress.value = i;
+            await new Promise((res) => setTimeout(res));
+          }
+          try {
+            connections.push(new RTCPeerConnection());
+            console.log("Error: was able to create more than 500 connections");
+            loadingDiv.innerText =
+              "Error: was not able to block webrtc ERROR_A";
+          } catch (error) {
+            try {
+              new isolatedContextTest.contentWindow.RTCPeerConnection();
+              console.log(
+                "Error: was able to create more than 500 connections, iframe is probably isolated"
+              );
+              loadingDiv.innerText =
+                "Error: was not able to block webrtc ERROR_C";
+            } catch (error) {
+              loadingDiv.innerHTML = "";
+              iframe.src = "index.html";
+              iframe.contentWindow.webxdc_internal = window.webxdc_internal;
+              iframe.contentWindow.webxdc = window.webxdc;
+            }
+          }
+        } catch (error) {
+          console.log(
+            "error loading, should crash / close webxdc activity",
+            error
+          );
+          loadingDiv.innerText = "Error: was not able to block webrtc ERROR_B";
+        }
+
+        return Object.freeze({
+          len: () => {
+            return connections.length;
+          },
+        });
+      })();
+    </script>
+  </body>
+</html>

src/org/thoughtcrime/securesms/WebxdcActivity.java

@@ -40,6 +40,7 @@ import org.thoughtcrime.securesms.util.Prefs;
 import org.thoughtcrime.securesms.util.Util;
 
 import java.io.ByteArrayInputStream;
+import java.io.IOException;
 import java.io.InputStream;
 
 public class WebxdcActivity extends WebViewActivity implements DcEventCenter.DcEventDelegate  {
@@ -121,6 +122,7 @@ public class WebxdcActivity extends WebViewActivity implements DcEventCenter.DcE
     webSettings.setJavaScriptEnabled(true);
     webSettings.setAllowFileAccess(false);
     webSettings.setBlockNetworkLoads(!internetAccess);
+    webView.setNetworkAvailable(internetAccess);
     webSettings.setAllowContentAccess(false);
     webSettings.setGeolocationEnabled(false);
     webSettings.setAllowFileAccessFromFileURLs(false);
@@ -129,7 +131,17 @@ public class WebxdcActivity extends WebViewActivity implements DcEventCenter.DcE
     webSettings.setDomStorageEnabled(true);
     webView.addJavascriptInterface(new InternalJSApi(), "InternalJSApi");
 
-    webView.loadUrl(this.baseURL + "/index.html");
+
+    InputStream bootstrap_stream = getResources().openRawResource(R.raw.webxdc_wrapper);
+    byte[] bootstrap_bytes = new byte[0];
+    try {
+      bootstrap_bytes = new byte[bootstrap_stream.available()];
+      bootstrap_stream.read(bootstrap_bytes);
+      String bootstrapHtml = new String(bootstrap_bytes);
+      webView.loadDataWithBaseURL(this.baseURL + "/webxdc_bootstrap324567869.html", bootstrapHtml, "text/html", "UTF-8", null);
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
 
     Util.runOnAnyBackgroundThread(() -> {
       final DcChat chat = dcContext.getChat(dcAppMsg.getChatId());
@@ -170,10 +182,6 @@ public class WebxdcActivity extends WebViewActivity implements DcEventCenter.DcE
 
   @Override
   protected boolean openOnlineUrl(String url) {
-    if (url.startsWith(baseURL +"/")) {
-      // internal page, continue loading in the WebView
-      return false;
-    }
     if (url.startsWith("mailto:")) {
       return super.openOnlineUrl(url);
     }