Introduce the ANNOTATE_LEAKING_OBJECT_PTR annotation that can be used to mark

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 # running overnight and removing outdated bugs/suppressions.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 125 matching lines @@
 {
    Intentional leak of *Histograms to avoid shutdown races
    Heapcheck:Leak
    ...
    fun:base::*Histogram::FactoryGet
 }
 {
    Intentional leak of stats histogram to avoid shutdown races
    Heapcheck:Leak
    ...
-   fun:disk_cache::StatsHistogram::StatsHistogramFactoryGet
+   fun:disk_cache::StatsHistogram::FactoryGet
 }
 {
    String name pushed into deliberately leaked histograms
    Heapcheck:Leak
    ...
    fun:basic_string
    fun:base:*:HistogramTest_*_Test::TestBody
 }
 {
    String name pushed into deliberately leaked ScoketPool histigram
@@ skipping 1231 matching lines @@
    Heapcheck:Leak
    ...
    fun:WebCore::CSSStyleApplyProperty::sharedCSSStyleApplyProperty
    ...
    fun:CSSStyleSelector
    ...
    fun:WebCore::HTMLConstructionSite::*
    ...
    fun:WebCore::HTMLTreeBuilder::*
 }