Introduce the ANNOTATE_LEAKING_OBJECT_PTR annotation that can be used to mark

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 # running overnight and removing outdated bugs/suppressions.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 855 matching lines @@
    Memcheck:Leak
    fun:_Znw*
    ...
    fun:_ZN4base*Histogram10FactoryGet*
 }
 {
    # Histograms are used on un-joined threads, and can't be deleted atexit.
    Histograms via FactoryGet including Stats for disk_cache
    Memcheck:Leak
    fun:_Znw*
-   fun:_ZN10disk_cache14StatsHistogram24StatsHistogramFactoryGet*
+   fun:_ZN10disk_cache14StatsHistogram10FactoryGet*
 }
 
 #-----------------------------------------------------------------------
 # 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).
 
 {
    # Chromium flakily leaks tasks at shutdown, see
    # http://crbug.com/6532
    # http://codereview.chromium.org/20067
@@ skipping 3809 matching lines @@
 }
 {
    bug_todo_getdelim2
    Memcheck:Leak
    fun:malloc
    fun:getdelim
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
    obj:/lib/libselinux.so.1
 }