Make max width for file tree depend on screen width

app/assets/javascripts/diffs/components/app.vue

@@ -26,7 +26,6 @@ import {
   TREE_LIST_WIDTH_STORAGE_KEY,
   INITIAL_TREE_WIDTH,
   MIN_TREE_WIDTH,
-  MAX_TREE_WIDTH,
   TREE_HIDE_STATS_WIDTH,
   MR_TREE_SHOW_KEY,
   CENTERED_LIMITED_CONTAINER_CLASSES,
@@ -632,7 +631,7 @@ export default {
     },
   },
   minTreeWidth: MIN_TREE_WIDTH,
-  maxTreeWidth: MAX_TREE_WIDTH,
+  maxTreeWidth: window.innerWidth / 2,
   howToMergeDocsPath: helpPagePath('user/project/merge_requests/reviews/index.md', {
     anchor: 'checkout-merge-requests-locally-through-the-head-ref',
   }),

app/assets/javascripts/diffs/constants.js

@@ -42,7 +42,6 @@ export const TREE_LIST_WIDTH_STORAGE_KEY = 'mr_tree_list_width';
 
 export const INITIAL_TREE_WIDTH = 320;
 export const MIN_TREE_WIDTH = 240;
-export const MAX_TREE_WIDTH = 400;
 export const TREE_HIDE_STATS_WIDTH = 260;
 
 export const OLD_LINE_KEY = 'old_line';