Unify code applying the colors of a process

We had some duplication because the `css_for_process_header` was using
an instance variable, and so it couldn't be called from a partial where
this instance variable wasn't available.

Using a local variable and passing it as a parameter (as we should
always do) solves the issue and lets us simplify the code.

app/helpers/legislation_helper.rb

@@ -18,13 +18,13 @@ module LegislationHelper
     }
   end
 
-  def banner_color?
+  def banner_color?(process)
-    @process.background_color.present? && @process.font_color.present?
+    process.background_color.present? && process.font_color.present?
   end
 
-  def css_for_process_header
+  def css_for_process_header(process)
-    if banner_color?
+    if banner_color?(process)
-      "background: #{@process.background_color};color: #{@process.font_color};"
+      "background: #{process.background_color};color: #{process.font_color};"
     end
   end
 end

app/views/legislation/processes/_header.html.erb

@@ -1,8 +1,8 @@
-<div class="legislation-hero jumbo" style="<%= css_for_process_header %>">
+<div class="legislation-hero jumbo" style="<%= css_for_process_header(@process) %>">
   <div class="row">
     <div class="small-12 medium-9 column">
 
-      <% if banner_color? %>
+      <% if banner_color?(@process) %>
         <%= link_to t("shared.back"),
                     legislation_processes_path,
                     class: "icon-angle-left",

app/views/legislation/processes/_header_full.html.erb

@@ -12,10 +12,7 @@
     <%= markdown @process.additional_info if @process.additional_info %>
   </div>
 
-  <button type="button" class="button" data-toggle="additional_info"
+  <button type="button" class="button" data-toggle="additional_info" style="<%= css_for_process_header(process) %>">
-    <% if banner_color? %>
-      style="background:<%= process.font_color %>; color:<%= process.background_color %>;"
-    <% end %>>
     <%= t("legislation.processes.header.additional_info") %>
   </button>
 <% end %>

spec/helpers/legislation_helper_spec.rb

@@ -9,23 +9,23 @@ describe LegislationHelper do
 
   describe "banner colors presence" do
     it "background and font color exist" do
-      @process = build(:legislation_process, background_color: "#944949", font_color: "#ffffff")
+      process = build(:legislation_process, background_color: "#944949", font_color: "#ffffff")
-      expect(banner_color?).to be true
+      expect(banner_color?(process)).to be true
     end
 
     it "background color exist and font color not exist" do
-      @process = build(:legislation_process, background_color: "#944949", font_color: "")
+      process = build(:legislation_process, background_color: "#944949", font_color: "")
-      expect(banner_color?).to be false
+      expect(banner_color?(process)).to be false
     end
 
     it "background color not exist and font color exist" do
-      @process = build(:legislation_process, background_color: "", font_color: "#944949")
+      process = build(:legislation_process, background_color: "", font_color: "#944949")
-      expect(banner_color?).to be false
+      expect(banner_color?(process)).to be false
     end
 
     it "background and font color not exist" do
-      @process = build(:legislation_process, background_color: "", font_color: "")
+      process = build(:legislation_process, background_color: "", font_color: "")
-      expect(banner_color?).to be false
+      expect(banner_color?(process)).to be false
     end
   end
 end