[Mac] Fix a leak in HyperlinkButtonCell

tools/valgrind/memcheck/suppressions_mac.txt

 # There are three kinds of suppressions in this file:
 # 1. Third party stuff we have no control over.
 #
 # 2. Intentional unit test errors, 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.
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 357 matching lines @@
    fun:sqlite3LockAndPrepare
    fun:sqlite3_prepare_v2
    fun:_ZN3sql10Connection18GetUniqueStatementEPKc
    fun:_ZN3sql10Connection18GetCachedStatementERKNS_11StatementIDEPKc
    fun:_ZN7history13VisitDatabase12GetStartDateEPN4base4TimeE
    fun:_ZN7history14HistoryBackend8InitImplEv
    fun:_ZN7history14HistoryBackend4InitEb
    fun:_Z16DispatchToMethodIN7history14HistoryBackendEMS1_FvbEbEvPT_T0_RK6Tuple1IT1_E
    fun:_ZN14RunnableMethodIN7history14HistoryBackendEMS1_FvbE6Tuple1IbEE3RunEv
 }
-{
-   bug_27149
-   Memcheck:Leak
-   fun:malloc_zone_calloc
-   fun:_internal_class_createInstanceFromZone
-   fun:+[NSObject allocWithZone:]
-   fun:-[NSParagraphStyle mutableCopyWithZone:]
-   fun:-[NSObject mutableCopy]
-   fun:-[HyperlinkButtonCell linkAttributes]
-   fun:-[HyperlinkButtonCell drawTitle:withFrame:inView:]
-   fun:-[NSButtonCell _configureAndDrawTitleWithRect:cellFrame:controlView:]
-   fun:-[NSButtonCell drawInteriorWithFrame:inView:]
-   fun:-[NSControl drawRect:]
-   fun:-[NSView _drawRect:clip:]
-   fun:-[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:]
-   fun:-[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:]
-   fun:-[NSView _recursiveDisplayAllDirtyWithLockFocus:visRect:]
-   fun:-[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]
-   fun:-[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]
-   fun:-[NSView _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]
-   fun:-[NSThemeFrame _recursiveDisplayRectIfNeededIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:topView:]
-   fun:-[NSView _displayRectIgnoringOpacity:isVisibleRect:rectIsVisibleRectForView:]
-   fun:-[NSView displayIfNeeded]
-   fun:-[NSWindow displayIfNeeded]
-   fun:_handleWindowNeedsDisplay
-}