Heapchecker suppression for new leaks in net_unittests.

tools/heapcheck/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 # running overnight and removing outdated bugs/suppressions.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 944 matching lines @@
    fun:PluginService::Observe
    fun:NotificationService::Notify
    fun:ExtensionsService::NotifyExtensionLoaded
    fun:ExtensionsService::OnExtensionLoaded
    fun:ExtensionsService::LoadInstalledExtension
    fun:ExtensionsService::ContinueLoadAllExtensions
    fun:ExtensionsService::LoadAllExtensions
    fun:ExtensionsService::Init
    fun:ExtensionsServiceTest_CleanupOnStartup_Test::TestBody
 }
+{
+   bug_53141
+   Heapcheck:Leak
+   ...
+   fun:disk_cache::EntryImpl::PrepareTarget
+   fun:disk_cache::EntryImpl::WriteDataImpl
+   fun:disk_cache::BackendIO::ExecuteEntryOperation
+   fun:disk_cache::BackendIO::ExecuteOperation
+   fun:void DispatchToMethod
+   fun:RunnableMethod::Run
+   fun:MessageLoop::RunTask
+}