Add a supression for a leak on Linux. I'm not really sure of the exact reaso...

tools/valgrind/memcheck/suppressions.txt

 # There are three 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 # running overnight and removing outdated bugs/suppressions.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 729 matching lines @@
    Memcheck:Leak
    fun:_Znwj
    fun:_ZN7history20VisitSegmentDatabase17QuerySegmentUsageERKN4base4TimeEiPSt6vectorIP13PageUsageDataSaIS7_EE
    #fun:_ZN7history14HistoryBackend24QueryTopURLsAndRedirectsE13scoped_refptrI18CancelableRequest1I14CallbackRunnerI6Tuple2IPSt6vectorI4GURLSaIS6_EEPSt3mapIS6_S1_I16RefCountedVectorIS6_EESt4lessIS6_ESaISt4pairIKS6_SD_EEEEES4_IS8_SK_EEEi
 }
 {
    bug_16128
    Memcheck:Leak
    fun:_Znwj
    fun:_ZN3IPC11SyncChannelC1ERKSsNS_7Channel4ModeEPNS3_8ListenerEPNS_12ChannelProxy13MessageFilterEP11MessageLoopbPN4base13WaitableEventE
-   fun:_ZN11ChildThread4InitEv
-   fun:_ZN12RenderThread4InitEv
+   fun:_ZN11ChildThreadC2Ev
+   fun:_ZN12RenderThreadC1Ev
+   fun:_Z12RendererMainRK18MainFunctionParams
+   fun:ChromeMain
+   fun:main
 }
 {
    bug_16129
    Memcheck:Leak
    fun:_Znwj
    fun:_Z11NewCallbackI11WebViewImplPN11webkit_glue20ImageResourceFetcherERK8SkBitmapEPN9Callback2IT0_T1_E4TypeEPT_MSD_FvS8_S9_E
    fun:_ZN11WebViewImpl13DownloadImageEiRK4GURLi
    fun:_ZN10RenderView15OnDownloadImageEiRK4GURLi
 }
 {
@@ skipping 201 matching lines @@
    fun:_ZN7WebCore14ChromiumBridge19clipboardWriteImageEPK15NativeImageSkiaRKNS_4KURLERKNS_6StringE
    fun:_ZN7WebCore10Pasteboard10writeImageEPNS_4NodeERKNS_4KURLERKNS_6StringE
 }
 {
    # Only in test shell
    bug_17188
    Memcheck:Addr4
    fun:_ZN9TestShell10ClosePopupEv
    fun:_ZN12_GLOBAL__N_119MainWindowLostFocusEP10_GtkWidgetP14_GdkEventFocusP9TestShell
 }