[content shell] don't leak the devtools delegate

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 # running overnight and removing outdated bugs/suppressions.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 7308 matching lines @@
    fun:_ZN7content21ShellBrowserMainParts22PostMainMessageLoopRunEv
    fun:_ZN7content15BrowserMainLoop25ShutdownThreadsAndCleanUpEv
    fun:_ZN7content21BrowserMainRunnerImpl8ShutdownEv
    fun:_Z16ShellBrowserMainRKN7content18MainFunctionParamsE
    fun:_ZN7content17ShellMainDelegate10RunProcessERKSsRKNS_18MainFunctionParamsE
    fun:_ZN7content23RunNamedProcessTypeMainERKSsRKNS_18MainFunctionParamsEPNS_19ContentMainDelegateE
    fun:_ZN7content21ContentMainRunnerImpl3RunEv
    fun:_ZN7content11ContentMainEiPPKcPNS_19ContentMainDelegateE
 }
 {
-   bug_246359
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN7content21ShellBrowserMainParts21PreMainMessageLoopRunEv
-   fun:_ZN7content15BrowserMainLoop13CreateThreadsEv
-   fun:_ZN7content21BrowserMainRunnerImpl10InitializeERKNS_18MainFunctionParamsE
-   fun:_Z16ShellBrowserMainRKN7content18MainFunctionParamsE
-   fun:_ZN7content17ShellMainDelegate10RunProcessERKSsRKNS_18MainFunctionParamsE
-   fun:_ZN7content23RunNamedProcessTypeMainERKSsRKNS_18MainFunctionParamsEPNS_19ContentMainDelegateE
-   fun:_ZN7content21ContentMainRunnerImpl3RunEv
-   fun:_ZN7content11ContentMainEiPPKcPNS_19ContentMainDelegateE
-}
-{
    bug_245866
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN4base23EnsureProcessTerminatedEi
    fun:_ZN7content6Zygote17HandleReapRequestEiRK6Pickle14PickleIterator
    fun:_ZN7content6Zygote24HandleRequestFromBrowserEi
    fun:_ZN7content6Zygote15ProcessRequestsEv
    fun:_ZN7content10ZygoteMainERKNS_18MainFunctionParamsEPNS_18ZygoteForkDelegateE
    fun:_ZN7content9RunZygoteERKNS_18MainFunctionParamsEPNS_19ContentMainDelegateE
    fun:_ZN7content23RunNamedProcessTypeMainERKSsRKNS_18MainFunctionParamsEPNS_19ContentMainDelegateE
@@ skipping 28 matching lines @@
 {
    bug_246306
    Memcheck:Leak
    fun:_Znw*
    fun:_ZN4base8internal20PostTaskAndReplyImpl16PostTaskAndReplyERKN15tracked_objects8LocationERKNS_8CallbackIFvvEEESA_
    fun:_ZN4base10TaskRunner16PostTaskAndReplyERKN15tracked_objects8LocationERKNS_8CallbackIFvvEEES9_
    fun:_ZN6syncer14GetSessionNameERK13scoped_refptrIN4base10TaskRunnerEERKNS1_8CallbackIFvRKSsEEE
    fun:_ZN12browser_sync10DeviceInfo21CreateLocalDeviceInfoEN4base8CallbackIFvRKS0_EEE
    fun:_ZN30ManagedUserRegistrationService8RegisterERKSbItN4base20string16_char_traitsESaItEERKNS0_8CallbackIFvRK22GoogleServiceAuthErrorRKSsEEE
 }