Add paste samples to list view.

Summary:
This adds a "body" field to `PhabricatorObjectItemView` which lets you optionally
add more information to the list view. It then uses this new field to show
samples of pastes in the paste list view.

Test Plan:
{F27147}

{F27148}

Reviewers: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4188

src/applications/paste/controller/PhabricatorPasteController.php

@@ -39,4 +39,31 @@ abstract class PhabricatorPasteController extends PhabricatorController {
     return $crumbs;
   }
 
+  public function buildSourceCodeView(
+    PhabricatorPaste $paste,
+    PhabricatorFile $file,
+    $max_lines = null) {
+
+    $language = $paste->getLanguage();
+    $source = $file->loadFileData();
+
+    if (empty($language)) {
+      $source = PhabricatorSyntaxHighlighter::highlightWithFilename(
+        $paste->getTitle(),
+        $source);
+    } else {
+      $source = PhabricatorSyntaxHighlighter::highlightWithLanguage(
+        $language,
+        $source);
+    }
+
+    $lines = explode("\n", $source);
+
+    if ($max_lines) {
+      $lines = array_slice($lines, 0, $max_lines);
+    }
+
+    return id(new PhabricatorSourceCodeView())
+      ->setLines($lines);
+  }
 }