Introduce FastShowPickler which will be used for app list cold start.

chrome/chrome_browser_ui.gypi

Index: chrome/chrome_browser_ui.gypi
diff --git a/chrome/chrome_browser_ui.gypi b/chrome/chrome_browser_ui.gypi
index 0d1a1a802be36968ed5483f3039b83de3f15d320..f6cb65aaf0aab75d52edab04f5763f71687d3d68 100644
--- a/chrome/chrome_browser_ui.gypi
+++ b/chrome/chrome_browser_ui.gypi
@@ -108,6 +108,8 @@
         'browser/ui/android/website_settings_popup_android.h',
         'browser/ui/android/window_android_helper.cc',
         'browser/ui/android/window_android_helper.h',
+        'browser/ui/app_list/fast_show_pickler.cc',
+        'browser/ui/app_list/fast_show_pickler.h',
         'browser/ui/app_list/app_context_menu.cc',
         'browser/ui/app_list/app_context_menu.h',
         'browser/ui/app_list/app_context_menu_delegate.h',
@@ -3114,5 +3116,22 @@
         }],
       ],
     },
+    {
+      # Unit tests for chrome app list, not run on any bots, this is for faster
+      # compile/link/test cycles during development.
+      'target_name': 'chrome_app_list_unit_tests',
+      'type': '<(gtest_target_type)',
+      'dependencies': [
+        '../skia/skia.gyp:skia',
+        '../testing/gtest.gyp:gtest',
+        '../ui/app_list/app_list.gyp:app_list',
+        'apps',
+        'browser_ui',
+      ],
+      'sources': [
+        'browser/ui/app_list/chrome_app_list_unit_tests.cc',
+        'browser/ui/app_list/fast_show_pickler_unittest.cc',
+      ],
+    },
   ],
 }