Add missing newline in chrome_browser.gypi.

The CL https://codereview.chromium.org/415343002/ accidentally
introduced new files in //chrome/chrome_browser.gypi without
adding a newline.

This CL just cleans up the style of the .gypi.

BUG=383630

Review URL: https://codereview.chromium.org/533173003

Cr-Commit-Position: refs/heads/master@{#293204}

chrome/chrome_browser.gypi

@@ -13,7 +13,8 @@
       'browser/about_flags.cc',
       'browser/about_flags.h',
       'browser/android/accessibility/font_size_prefs_android.cc',
-      'browser/android/accessibility/font_size_prefs_android.h',      'browser/android/accessibility_util.cc',
+      'browser/android/accessibility/font_size_prefs_android.h',
+      'browser/android/accessibility_util.cc',
       'browser/android/accessibility_util.h',
       'browser/android/activity_type_id_list.h',
       'browser/android/activity_type_ids.cc',