make "browse in diffusion" action work for commits in branches other than master

Summary: we do this by passing the "seenOnBranches" commit data detail through the stack

Test Plan: browse in diffusion link worked for non-master checkins under git

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1949

Differential Revision: https://secure.phabricator.com/D3853

src/applications/differential/view/DifferentialChangesetListView.php

@@ -32,9 +32,18 @@ final class DifferentialChangesetListView extends AphrontView {
   private $user;
   private $symbolIndexes = array();
   private $repository;
+  private $branch;
   private $diff;
   private $vsMap = array();
 
+  public function setBranch($branch) {
+    $this->branch = $branch;
+    return $this;
+  }
+  private function getBranch() {
+    return $this->branch;
+  }
+
   public function setChangesets($changesets) {
     $this->changesets = $changesets;
     return $this;
@@ -257,7 +266,8 @@ final class DifferentialChangesetListView extends AphrontView {
     if ($repository) {
       $meta['diffusionURI'] = (string)$repository->getDiffusionBrowseURIForPath(
         $changeset->getAbsoluteRepositoryPath($repository, $this->diff),
-        idx($changeset->getMetadata(), 'line:first'));
+        idx($changeset->getMetadata(), 'line:first'),
+        $this->getBranch());
     }
 
     $change = $changeset->getChangeType();

src/applications/diffusion/controller/DiffusionCommitController.php

@@ -269,6 +269,10 @@ final class DiffusionCommitController extends DiffusionController {
       $change_list->setRenderURI('/diffusion/'.$callsign.'/diff/');
       $change_list->setRepository($repository);
       $change_list->setUser($user);
+      // pick the first branch for "Browse in Diffusion" View Option
+      $branches     = $commit_data->getCommitDetail('seenOnBranches');
+      $first_branch = reset($branches);
+      $change_list->setBranch($first_branch);
 
       $change_list->setStandaloneURI(
         '/diffusion/'.$callsign.'/diff/');

src/applications/repository/storage/PhabricatorRepository.php

@@ -60,11 +60,14 @@ final class PhabricatorRepository extends PhabricatorRepositoryDAO {
     return $this;
   }
 
-  public function getDiffusionBrowseURIForPath($path, $line = null) {
+  public function getDiffusionBrowseURIForPath($path,
+                                               $line = null,
+                                               $branch = null) {
     $drequest = DiffusionRequest::newFromDictionary(
       array(
         'repository' => $this,
         'path'       => $path,
+        'branch'     => $branch,
       ));
 
     return $drequest->generateURI(