Cache highlighted diff lines for merge requests

Introducing the concept of SafeDiffs which relates 
diffs with UI highlighting.

7 files changed, 9 insertions, 10 deletions

diff --git a/app/views/projects/commit/show.html.haml b/app/views/projects/commit/show.html.haml
index d0da2606587..11b2020f99b 100644
--- a/app/views/projects/commit/show.html.haml
+++ b/app/views/projects/commit/show.html.haml
@@ -7,7 +7,7 @@
   = render "ci_menu"
 - else
   %div.block-connector
-= render "projects/diffs/diffs", diffs: @diffs, project: @project, diff_refs: @commit.diff_refs
+= render "projects/diffs/diffs", diff_files: @diffs.diff_files, project: @diffs.project, diff_refs: @diffs.diff_refs
 = render "projects/notes/notes_with_form"
 - if can_collaborate_with_project?
   - %w(revert cherry-pick).each do |type|
diff --git a/app/views/projects/compare/show.html.haml b/app/views/projects/compare/show.html.haml
index 28a50e7031a..eb8a1bd5289 100644
--- a/app/views/projects/compare/show.html.haml
+++ b/app/views/projects/compare/show.html.haml
@@ -8,7 +8,7 @@
 
   - if @commits.present?
     = render "projects/commits/commit_list"
-    = render "projects/diffs/diffs", diffs: @diffs, project: @project, diff_refs: @diff_refs
+    = render "projects/diffs/diffs", diff_files: @diffs.diff_files, project: @diffs.project, diff_refs: @diffs.diff_refs
   - else
     .light-well
       .center
diff --git a/app/views/projects/diffs/_diffs.html.haml b/app/views/projects/diffs/_diffs.html.haml
index 4bf3ccace20..45895a9a3de 100644
--- a/app/views/projects/diffs/_diffs.html.haml
+++ b/app/views/projects/diffs/_diffs.html.haml
@@ -2,8 +2,6 @@
 - if diff_view == 'parallel'
   - fluid_layout true
 
-- diff_files = safe_diff_files(diffs, diff_refs: diff_refs, repository: project.repository)
-
 .content-block.oneline-block.files-changed
   .inline-parallel-buttons
     - if !expand_all_diffs? && diff_files.any? { |diff_file| diff_file.collapsed? }
diff --git a/app/views/projects/diffs/_file.html.haml b/app/views/projects/diffs/_file.html.haml
index 1854c64cbd7..f914e13a1ec 100644
--- a/app/views/projects/diffs/_file.html.haml
+++ b/app/views/projects/diffs/_file.html.haml
@@ -15,6 +15,6 @@
                 from_merge_request_id: @merge_request.id,
                 skip_visible_check: true)
 
-        = view_file_btn(diff_commit.id, diff_file, project)
+        = view_file_btn(diff_commit.id, diff_file.new_path, project)
 
-  = render 'projects/diffs/content', diff_file: diff_file, diff_commit: diff_commit, diff_refs: diff_refs, blob: blob, project: project
+  = render 'projects/diffs/content', diff_file: diff_file, diff_commit: diff_commit, blob: blob, project: project
diff --git a/app/views/projects/diffs/_text_file.html.haml b/app/views/projects/diffs/_text_file.html.haml
index 5970b9abf2b..a483927671e 100644
--- a/app/views/projects/diffs/_text_file.html.haml
+++ b/app/views/projects/diffs/_text_file.html.haml
@@ -5,7 +5,7 @@
 
 %table.text-file.code.js-syntax-highlight{ data: diff_view_data, class: too_big ? 'hide' : '' }
   - last_line = 0
-  - diff_file.highlighted_diff_lines.each do |line|
+  - diff_file.diff_lines.each do |line|
     - last_line = line.new_pos
     = render "projects/diffs/line", line: line, diff_file: diff_file
 
diff --git a/app/views/projects/merge_requests/_new_submit.html.haml b/app/views/projects/merge_requests/_new_submit.html.haml
index a5e67b95727..cb2b623691c 100644
--- a/app/views/projects/merge_requests/_new_submit.html.haml
+++ b/app/views/projects/merge_requests/_new_submit.html.haml
@@ -42,7 +42,7 @@
           %h4 This comparison includes more than #{MergeRequestDiff::COMMITS_SAFE_SIZE} commits.
           %p To preserve performance the line changes are not shown.
       - else
-        = render "projects/diffs/diffs", diffs: @diffs, project: @project, diff_refs: @merge_request.diff_refs, show_whitespace_toggle: false
+        = render "projects/diffs/diffs", diff_files: @diffs.diff_files, project: @diffs.project, diff_refs: @merge_request.diff_refs, show_whitespace_toggle: false
     - if @pipeline
       #builds.builds.tab-pane
         = render "projects/merge_requests/show/builds"
diff --git a/app/views/projects/merge_requests/show/_diffs.html.haml b/app/views/projects/merge_requests/show/_diffs.html.haml
index 1b0bae86ad4..ed2765356db 100644
--- a/app/views/projects/merge_requests/show/_diffs.html.haml
+++ b/app/views/projects/merge_requests/show/_diffs.html.haml
@@ -1,6 +1,7 @@
 - if @merge_request_diff.collected?
-  = render "projects/diffs/diffs", diffs: @merge_request.diffs(diff_options),
-    project: @merge_request.project, diff_refs: @merge_request.diff_refs
+  - diffs = SafeDiffs::MergeRequest.new(@merge_request, diff_options: diff_options)
+  = render "projects/diffs/diffs", diff_files: diffs.diff_files,
+    diff_refs: diffs.diff_refs, project: diffs.project
 - elsif @merge_request_diff.empty?
   .nothing-here-block Nothing to merge from #{@merge_request.source_branch} into #{@merge_request.target_branch}
 - else