Suppress leaks in sync_file_system::SyncFileSystemBackend

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 # running overnight and removing outdated bugs/suppressions.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 7221 matching lines @@
    fun:_ZN3net19QuicPacketGenerator22SerializeAndSendPacketEv
    fun:_ZN3net19QuicPacketGenerator16SendQueuedFramesEv
    fun:_ZN3net19QuicPacketGenerator15AddControlFrameERKNS_9QuicFrameE
    fun:_ZN3net14QuicConnection13SendRstStreamEjNS_22QuicRstStreamErrorCodeE
    fun:_ZN3net11QuicSession13SendRstStreamEjNS_22QuicRstStreamErrorCodeE
    fun:_ZN3net17QuicClientSession13SendRstStreamEjNS_22QuicRstStreamErrorCodeE
    fun:_ZN3net18ReliableQuicStream5CloseENS_22QuicRstStreamErrorCodeE
    fun:_ZN3net14QuicHttpStream5CloseEb
    fun:_ZN3net4test40QuicStreamFactoryTest_MaxOpenStream_Test8TestBodyEv
 }
+{
+   bug_282646
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN16sync_file_system21SyncFileSystemBackendC1EP7Profile
+   fun:_ZN6chrome26ChromeContentBrowserClient31GetAdditionalFileSystemBackendsEPN7content14BrowserContextERKN4base8FilePathEP12ScopedVectorIN7fileapi17FileSystemBackendEE
+   fun:_ZN7content23CreateFileSystemContextEPNS_14BrowserContextERKN4base8FilePathEbPN5quota17QuotaManagerProxyE
+   fun:_ZN7content20StoragePartitionImpl6CreateEPNS_14BrowserContextEbRKN4base8FilePathE
+   fun:_ZN7content23StoragePartitionImplMap3GetERKSsS2_b
+   fun:_ZN7content12_GLOBAL__N_129GetStoragePartitionFromConfigEPNS_14BrowserContextERKSsS4_b
+}