Suppress leaks in sync_file_system::SyncFileSystemBackend

tools/heapcheck/suppressions.txt

Index: tools/heapcheck/suppressions.txt
diff --git a/tools/heapcheck/suppressions.txt b/tools/heapcheck/suppressions.txt
index f0ceab2fff43d8c0b06b659ad7920293dacc7941..b09801819823125d57c42df7c54338c8bd14e506 100644
--- a/tools/heapcheck/suppressions.txt
+++ b/tools/heapcheck/suppressions.txt
@@ -885,3 +885,19 @@
    fun:net::QuicHttpStream::Close
    fun:net::test::QuicStreamFactoryTest_MaxOpenStream_Test::TestBody
 }
+{
+   bug_282646
+   Heapcheck:Leak
+   ...
+   fun:SyncFileSystemBackend
+   fun:chrome::ChromeContentBrowserClient::GetAdditionalFileSystemBackends
+   fun:content::CreateFileSystemContext
+   fun:content::StoragePartitionImpl::Create
+   fun:content::StoragePartitionImplMap::Get
+   fun:GetStoragePartitionFromConfig
+   fun:content::BrowserContext::GetStoragePartitionForSite
+   fun:ExtensionService::NotifyExtensionUnloaded
+   fun:ExtensionService::UnloadExtension
+   fun:ExtensionService::AddExtension
+   fun:extensions::TestExtensionEnvironment::MakeExtension
+}