Suppress ChromiumOS AppCache leak.

tools/valgrind/memcheck/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 # running overnight and removing outdated bugs/suppressions.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 2734 matching lines @@
    fun:g_main_context_iterate
    fun:g_main_context_iteration
    fun:_ZN4base16MessagePumpForUI17RunWithDispatcherEPNS_11MessagePump8DelegateEPNS0_10DispatcherE
    fun:_ZN11MessageLoop11RunInternalEv
    fun:_ZN11MessageLoop10RunHandlerEv
    fun:_ZN16MessageLoopForUI3RunEPN4base16MessagePumpForUI10DispatcherE
    fun:_ZN59_GLOBAL__N_chrome_browser_browser_main.cc_00000000_F6B6498C16RunUIMessageLoopEP14BrowserProcess
    fun:_Z11BrowserMainRK18MainFunctionParams
    fun:ChromeMain
 }
+{
+   bug_42897
+   Memcheck:Leak
+   fun:malloc
+   fun:realloc
+   fun:_ZN6Pickle6ResizeEj
+   fun:_ZN6PickleC2Ei
+   fun:_ZN3IPC7MessageC2EijNS0_13PriorityValueE
+   fun:_ZN3IPC16MessageWithTupleI6Tuple1IiEEC2EijRKS1_IRKiE
+   fun:_ZN26AppCacheMsg_UnregisterHostC1ERKi
+   fun:_ZN20AppCacheBackendProxy14UnregisterHostEi
+   fun:_ZN8appcache27WebApplicationCacheHostImplD2Ev
+   fun:_ZN35RendererWebApplicationCacheHostImplD0Ev
+   fun:_ZN3WTF14deleteOwnedPtrIN6WebKit23WebApplicationCacheHostEEEvPT_
+   fun:_ZN3WTF6OwnPtrIN6WebKit23WebApplicationCacheHostEED1Ev
+   fun:_ZN7WebCore28ApplicationCacheHostInternalD0Ev
+   fun:_ZN3WTF14deleteOwnedPtrIN7WebCore28ApplicationCacheHostInternalEEEvPT_
+   fun:_ZN3WTF6OwnPtrIN7WebCore28ApplicationCacheHostInternalEED1Ev
+   fun:_ZN7WebCore20ApplicationCacheHostD1Ev
+   fun:_ZN3WTF14deleteOwnedPtrIN7WebCore20ApplicationCacheHostEEEvPT_
+   fun:_ZN3WTF6OwnPtrIN7WebCore20ApplicationCacheHostEED1Ev
+   fun:_ZN7WebCore14DocumentLoaderD2Ev
+   fun:_ZN6WebKit17WebDataSourceImplD0Ev
+   fun:_ZN3WTF10RefCountedIN7WebCore14DocumentLoaderEE5derefEv
+   fun:_ZN3WTF6RefPtrIN7WebCore14DocumentLoaderEED1Ev
+}