Support Spaces transactions

Summary:
Ref T8424. This adds crude integration with Paste's edit/view workflows: you can change the space a Paste appears in, see transactions, and get a policy callout.

Lots of rough edges and non-obviousness but it pretty much works.

Test Plan:
  - Created and updated Pastes.
  - Moved them between spaces, saw policy effects.
  - Read transactions.
  - Looked at feed.
  - Faked query to return no spaces, saw control and other stuff vanish.
  - Faked query to return no spaces, created pastes.
  - Tried to submit bad values and got errors.

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8424

Differential Revision: https://secure.phabricator.com/D13159

src/applications/spaces/application/PhabricatorSpacesApplication.php

@@ -15,7 +15,7 @@ final class PhabricatorSpacesApplication extends PhabricatorApplication {
   }
 
   public function getFontIcon() {
-    return 'fa-compass';
+    return 'fa-th-large';
   }
 
   public function getTitleGlyph() {

src/applications/spaces/phid/PhabricatorSpacesNamespacePHIDType.php

@@ -28,7 +28,10 @@ final class PhabricatorSpacesNamespacePHIDType
 
     foreach ($handles as $phid => $handle) {
       $namespace = $objects[$phid];
+      $monogram = $namespace->getMonogram();
+
       $handle->setName($namespace->getNamespaceName());
+      $handle->setURI('/'.$monogram);
     }
   }
 

src/applications/spaces/view/PhabricatorSpacesControl.php

@@ -0,0 +1,49 @@
+<?php
+
+final class PhabricatorSpacesControl extends AphrontFormControl {
+
+  private $object;
+
+  protected function shouldRender() {
+    // Render this control only if some Spaces exist.
+    return PhabricatorSpacesNamespaceQuery::getAllSpaces();
+  }
+
+  public function setObject(PhabricatorSpacesInterface $object) {
+    $this->object = $object;
+    return $this;
+  }
+
+  protected function getCustomControlClass() {
+    return '';
+  }
+
+  protected function getOptions() {
+    $viewer = $this->getUser();
+    $viewer_spaces = PhabricatorSpacesNamespaceQuery::getViewerSpaces($viewer);
+
+    $map = mpull($viewer_spaces, 'getNamespaceName', 'getPHID');
+    asort($map);
+
+    return $map;
+  }
+
+  public function renderInput() {
+    $viewer = $this->getUser();
+
+    $this->setLabel(pht('Space'));
+
+    $value = $this->getValue();
+    if ($value === null) {
+      $value = $viewer->getDefaultSpacePHID();
+    }
+
+    return AphrontFormSelectControl::renderSelectTag(
+      $value,
+      $this->getOptions(),
+      array(
+        'name' => $this->getName(),
+      ));
+  }
+
+}