Prevent Send on Enter in Fullscreen Remarkup Mode

Summary: Fixes T12138. Test for the presence of being in fullscreen mode, and disable send on enter if present. Side note, I'd love a first class "hasClass" type Javelin function.

Test Plan:
- Go to Conpherence
- Type some smack, see it send on enter
- Go fullscreen like a boss
- Let the words flow
- Close fullscreen, then send on enter.
- (might be nice someday to add a "submit" button to fullscreen editor)

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Maniphest Tasks: T12138

Differential Revision: https://secure.phabricator.com/D17590

src/applications/conpherence/controller/ConpherenceViewController.php

@@ -184,6 +184,7 @@ final class ConpherenceViewController extends
           id(new PhabricatorRemarkupControl())
           ->setUser($user)
           ->setName('text')
+          ->setSendOnEnter(true)
           ->setValue($draft->getDraft()));
 
       $status_view = phutil_tag(

src/view/form/control/PhabricatorRemarkupControl.php

@@ -5,6 +5,7 @@ final class PhabricatorRemarkupControl extends AphrontFormTextAreaControl {
   private $disableMacro = false;
   private $disableFullScreen = false;
   private $canPin;
+  private $sendOnEnter = false;
 
   public function setDisableMacros($disable) {
     $this->disableMacro = $disable;
@@ -25,6 +26,15 @@ final class PhabricatorRemarkupControl extends AphrontFormTextAreaControl {
     return $this->canPin;
   }
 
+  public function setSendOnEnter($soe) {
+    $this->sendOnEnter = $soe;
+    return $this;
+  }
+
+  public function getSendOnEnter() {
+    return $this->sendOnEnter;
+  }
+
   protected function renderInput() {
     $id = $this->getID();
     if (!$id) {
@@ -78,6 +88,7 @@ final class PhabricatorRemarkupControl extends AphrontFormTextAreaControl {
         ),
         'canPin' => $this->getCanPin(),
         'disabled' => $this->getDisabled(),
+        'sendOnEnter' => $this->getSendOnEnter(),
         'rootID' => $root_id,
         'autocompleteMap' => (object)array(
           64 => array( // "@"