Only build various flash/pnacl/ppapi code when they are enabled.

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 9b7b3a1f1a15a68775aac69bf4bf16ffd53d2587..f728b4e79777a4054e2dae3a1a29de91fc644e36 100644
--- a/chrome/chrome_browser_ui.gypi
+++ b/chrome/chrome_browser_ui.gypi
@@ -1048,8 +1048,6 @@
       'browser/ui/webui/fileicon_source.h',
       'browser/ui/webui/flags_ui.cc',
       'browser/ui/webui/flags_ui.h',
-      'browser/ui/webui/flash_ui.cc',
-      'browser/ui/webui/flash_ui.h',
       'browser/ui/webui/gcm_internals_ui.cc',
       'browser/ui/webui/gcm_internals_ui.h',
       'browser/ui/webui/history_ui.cc',
@@ -1843,6 +1841,8 @@
     'chrome_browser_ui_plugin_sources': [
       'browser/ui/hung_plugin_tab_helper.cc',
       'browser/ui/hung_plugin_tab_helper.h',
+      'browser/ui/webui/flash_ui.cc',
+      'browser/ui/webui/flash_ui.h',
     ],
     'chrome_browser_ui_policy_sources': [
       'browser/ui/webui/policy_ui.cc',
@@ -2611,7 +2611,6 @@
             '../media/media.gyp:media',
             '../mojo/mojo_base.gyp:mojo_system_impl',
             '../net/net.gyp:net_with_v8',
-            '../third_party/adobe/flash/flash_player.gyp:flapper_version_h',
             '../third_party/expat/expat.gyp:expat',
             '../third_party/leveldatabase/leveldatabase.gyp:leveldatabase',
             '../third_party/libjingle/libjingle.gyp:libjingle',
@@ -2671,6 +2670,7 @@
           'sources': [ '<@(chrome_browser_ui_plugin_sources)' ],
           'dependencies': [
             '../ppapi/ppapi_internal.gyp:ppapi_ipc',
+            '../third_party/adobe/flash/flash_player.gyp:flapper_version_h',
           ],
         }],
         ['safe_browsing==1', {