Added configurable welcome content for Phabricator home page.

Summary:
The welcome.enabled feature is turned on by default; unsure of
whether this is desired by upstream.

Test Plan:
Apply the patch and see the welcome content.  It's configurable
in the config.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D5339

conf/default.conf.php

@@ -849,6 +849,11 @@ return array(
   // Contains a list of uninstalled applications
   'phabricator.uninstalled-applications' => array(),
 
+// -- Welcome Screen -------------------------------------------------------- //
+
+  // The custom HTML content for the Phabricator welcome screen.
+  'welcome.html' => null,
+
 // -- Files ----------------------------------------------------------------- //
 
   // Lists which uploaded file types may be viewed in the browser. If a file

src/applications/config/option/PhabricatorCoreConfigOptions.php

@@ -135,6 +135,10 @@ final class PhabricatorCoreConfigOptions
         ->setLocked(true)
         ->setDescription(
           pht('Array containing list of Uninstalled applications.')),
+      $this->newOption('welcome.html', 'string', null)
+        ->setLocked(true)
+        ->setDescription(
+          pht('Custom HTML to show on the main Phabricator dashboard.')),
       );
   }
 

src/applications/directory/controller/PhabricatorDirectoryMainController.php

@@ -40,6 +40,11 @@ final class PhabricatorDirectoryMainController
       $tasks_panel = null;
     }
 
+    if (PhabricatorEnv::getEnvConfig('welcome.html') !== null) {
+      $welcome_panel = $this->buildWelcomePanel();
+    } else {
+      $welcome_panel = null;
+    }
     $jump_panel = $this->buildJumpPanel();
     $revision_panel = $this->buildRevisionPanel();
     $audit_panel = $this->buildAuditPanel();
@@ -47,6 +52,7 @@ final class PhabricatorDirectoryMainController
 
     $content = array(
       $jump_panel,
+      $welcome_panel,
       $unbreak_panel,
       $triage_panel,
       $revision_panel,
@@ -226,6 +232,16 @@ final class PhabricatorDirectoryMainController
     return $panel;
   }
 
+  private function buildWelcomePanel() {
+    $panel = new AphrontPanelView();
+    $panel->appendChild(
+      phutil_safe_html(
+        PhabricatorEnv::getEnvConfig('welcome.html')));
+    $panel->setNoBackground();
+
+    return $panel;
+  }
+
   private function buildTasksPanel() {
     $user = $this->getRequest()->getUser();
     $user_phid = $user->getPHID();