Eliminate unneeded calls to Repository#blob_at when listing commits with no path

CHANGELOG

@@ -120,6 +120,7 @@ v 8.11.0 (unreleased)
   - Fix a memory leak caused by Banzai::Filter::SanitizationFilter
   - Speed up todos queries by limiting the projects set we join with
   - Ensure file editing in UI does not overwrite commited changes without warning user
+  - Eliminate unneeded calls to Repository#blob_at when listing commits with no path
 
 v 8.10.6
   - Upgrade Rails to 4.2.7.1 for security fixes. !5781

app/helpers/commits_helper.rb

@@ -98,7 +98,16 @@ module CommitsHelper
   end
 
   def link_to_browse_code(project, commit)
-    if current_controller?(:projects, :commits)
+    if @path.blank?
+      return link_to(
+        "Browse Files",
+        namespace_project_tree_path(project.namespace, project, commit),
+        class: "btn btn-default"
+      )
+    end
+
+    return unless current_controller?(:projects, :commits)
+
     if @repo.blob_at(commit.id, @path)
       return link_to(
         "Browse File",
@@ -115,12 +124,6 @@ module CommitsHelper
       )
     end
   end
-    link_to(
-      "Browse Files",
-      namespace_project_tree_path(project.namespace, project, commit),
-      class: "btn btn-default"
-    )
-  end
 
   def revert_commit_link(commit, continue_to_path, btn_class: nil, has_tooltip: true)
     return unless current_user