Remove entry from vargrind's memory check suppressions.

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 # running overnight and removing outdated bugs/suppressions.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 3442 matching lines @@
    fun:_ZN7storage17FileSystemContext25CreateFileSystemOperationERKNS_13FileSystemURLEPN4base4File5ErrorE
 }
 {
    bug_417526
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN4base19SequencedWorkerPoolC1EmRKSs
    fun:_ZN16sync_file_system13drive_backend14SyncEngineTest5SetUpEv
 }
 {
-   bug_419364
-   Memcheck:Uninitialized
-   fun:_ZN8chromeos21IsExternalFileURLTypeEN7storage14FileSystemTypeE
-   fun:_ZN8chromeos12_GLOBAL__N_132CreateIsolatedURLFromVirtualPathERKN7storage17FileSystemContextERKN4base8FilePathE
-   fun:_ZN8chromeos12_GLOBAL__N_19URLHelper13RunOnUIThreadE10scoped_ptrIS1_N4base14DefaultDeleterIS1_EEE
-}
-{
    bug_419373
    Memcheck:Uninitialized
    fun:_ZNK5blink20InlineFlowBoxPainter49roundedFrameRectClampedToLineTopAndBottomIfNeededEv
    fun:_ZN5blink20InlineFlowBoxPainter28paintBoxDecorationBackgroundERNS_9PaintInfoERKNS_11LayoutPointE
    fun:_ZN5blink20InlineFlowBoxPainter5paintERNS_9PaintInfoERKNS_11LayoutPointENS_10LayoutUnitES6_
    fun:_ZN5blink13InlineFlowBox5paintERNS_9PaintInfoERKNS_11LayoutPointENS_10LayoutUnitES6_
    fun:_ZN5blink20InlineFlowBoxPainter5paintERNS_9PaintInfoERKNS_11LayoutPointENS_10LayoutUnitES6_
    fun:_ZN5blink13InlineFlowBox5paintERNS_9PaintInfoERKNS_11LayoutPointENS_10LayoutUnitES6_
    fun:_ZN5blink13RootInlineBox5paintERNS_9PaintInfoERKNS_11LayoutPointENS_10LayoutUnitES6_
 }