Conditionally allow Gerrit to load in IFrame

Introduce new configuration option (gerrit.canLoadInIFrame) to allow
loading Gerrit in IFrame. By default it is set to 'false' to keep
current behavior.

Change-Id: Ie13b6141a9dfb8a18348fc778fb5f6083f95bd14
Signed-off-by: Dariusz Luksza <dariusz@luksza.org>

Documentation/config-gerrit.txt

@@ -1913,6 +1913,13 @@ file containing the class must be placed in the `$site_path/lib` folder.
 +
 If not specified, the default no-op implementation is used.
 
+[[gerrit.canLoadInIFrame]]gerrit.canLoadInIFrame::
++
+For security reasons Gerrit will always jump out of iframe.
+Setting this option to true will prevent this behavior.
++
+By default false.
+
 [[gitweb]]
 === Section gitweb
 

gerrit-common/src/main/java/com/google/gerrit/common/data/HostPageData.java

@@ -40,6 +40,7 @@ public class HostPageData {
   public List<Message> messages;
   public Integer pluginsLoadTimeout;
   public boolean isNoteDbEnabled;
+  public boolean canLoadInIFrame;
 
   public static class Theme {
     public String backgroundColor;

gerrit-gwtui/src/main/java/com/google/gerrit/client/Gerrit.java

@@ -405,7 +405,9 @@ public class Gerrit implements EntryPoint {
 
   @Override
   public void onModuleLoad() {
-    UserAgent.assertNotInIFrame();
+    if (!canLoadInIFrame()) {
+      UserAgent.assertNotInIFrame();
+    }
     setXsrfToken();
 
     KeyUtil.setEncoderImpl(new KeyUtil.Encoder() {
@@ -507,6 +509,10 @@ public class Gerrit implements EntryPoint {
     }));
   }
 
+  private native boolean canLoadInIFrame() /*-{
+    return $wnd.gerrit_hostpagedata.canLoadInIFrame || false;
+  }-*/;
+
   private static void initHostname() {
     myHost = Location.getHostName();
     final int d1 = myHost.indexOf('.');

gerrit-httpd/src/main/java/com/google/gerrit/httpd/raw/HostPageServlet.java

@@ -90,6 +90,7 @@ public class HostPageServlet extends HttpServlet {
   private final SiteStaticDirectoryServlet staticServlet;
   private final boolean isNoteDbEnabled;
   private final Integer pluginsLoadTimeout;
+  private final boolean canLoadInIFrame;
   private final GetDiffPreferences getDiff;
   private volatile Page page;
 
@@ -116,6 +117,7 @@ public class HostPageServlet extends HttpServlet {
     staticServlet = ss;
     isNoteDbEnabled = migration.readChanges();
     pluginsLoadTimeout = getPluginsLoadTimeout(cfg);
+    canLoadInIFrame = cfg.getBoolean("gerrit", "canLoadInIFrame", false);
     getDiff = diffPref;
 
     String pageName = "HostPage.html";
@@ -322,6 +324,7 @@ public class HostPageServlet extends HttpServlet {
       pageData.version = Version.getVersion();
       pageData.isNoteDbEnabled = isNoteDbEnabled;
       pageData.pluginsLoadTimeout = pluginsLoadTimeout;
+      pageData.canLoadInIFrame = canLoadInIFrame;
 
       StringWriter w = new StringWriter();
       w.write("var " + HPD_ID + "=");