gtk: Fix memory leak in ThemeServiceGtk::LoadGtkValues.

tools/valgrind/memcheck/suppressions.txt

 # There are four kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 5770 matching lines @@
 }
 {
    bug_120353
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN4base8internal20PostTaskAndReplyImpl16PostTaskAndReplyERKN15tracked_objects8LocationERKNS_8CallbackIFvvEEESA_
    fun:_ZN4base10TaskRunner16PostTaskAndReplyERKN15tracked_objects8LocationERKNS_8CallbackIFvvEEES9_
    fun:_ZN7content13BrowserThread16PostTaskAndReplyENS0_2IDERKN15tracked_objects8LocationERKN4base8CallbackIFvvEEESB_
    fun:_ZN5gdata15GDataFileSystem37PostBlockingPoolSequencedTaskAndReplyERKSsRKN15tracked_objects8LocationERKN4base8CallbackIFvvEEESC_
 }
-{
-   bug_120118
-   Memcheck:Leak
-   ...
-   fun:gtk_widget_style_get
-   fun:_ZN15ThemeServiceGtk13LoadGtkValuesEv
-}
 
 #-----------------------------------------------------------------------
 # 4. These only occur on our Google workstations
 
 {
    bug_todo_getdelim
    Memcheck:Leak
    fun:malloc
    fun:getdelim
    ...
@@ skipping 10 matching lines @@
    obj:/lib/libselinux.so.1
 }
 {
    bug_todo_grep
    Memcheck:Leak
    fun:malloc
    obj:/bin/grep
    obj:/bin/grep
 }