Turn on -Wdelete-non-virtual-dtor for chromeos as well.

All of the changes in this CL are to shut up the warning, not because of real problems (I fixed these in separate CLs).
See the bug for a disussion of this change.

BUG=84424
TEST=none

Review URL: http://codereview.chromium.org/6995085

git-svn-id: http://src.chromium.org/svn/trunk/src/build@88385 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -1353,18 +1353,6 @@
                 ],
               }]],
           }],
-          ['clang==1 and chromeos==1', {
-            'target_conditions': [
-              ['_toolset=="target"', {
-                'cflags': [
-                  # TODO(thakis): Remove this once all instances of this
-                  # are fixed in the views and chromeos code.
-                  # http://crbug.com/84424
-                  # TODO(thakis): Add back in when rolling clang past r131989
-                  '-Wno-delete-non-virtual-dtor',
-                ],
-              }]],
-          }],
           ['clang==1 and clang_use_chrome_plugins==1', {
             'target_conditions': [
               ['_toolset=="target"', {