Bug 1829203 - Fix valgrind suppression in Skia. r=aosmond

Differential Revision: https://phabricator.services.mozilla.com/D176074

build/valgrind/x86_64-pc-linux-gnu.sup

@@ -1034,17 +1034,3 @@
    ...
    fun:_ZN7mozilla3dom7Element7SetAttrEiP6nsAtomS3_RK12nsTSubstringIDsEP12nsIPrincipalb
 }
-
-# Skia's SkSTArenaAlloc can sometimes confuse valgrind. April 15, 2023. See bug 1821512.
-# Upstream Chrome/Skia issue 14254, https://bugs.chromium.org/p/skia/issues/detail?id=14254
-{
-   Bug 1821512
-   Memcheck:Addr8
-   fun:_ZN23SkRasterPipelineBlitter6CreateE*
-   fun:_Z29SkCreateRasterPipelineBlitter*
-   fun:_ZZN9SkBlitter6ChooseE*
-   fun:_ZN9SkBlitter6ChooseE*
-   fun:choose
-   fun:_ZN19SkAutoBlitterChooseC2E*
-   ...
-}

gfx/skia/skia/src/base/SkArenaAlloc.h

@@ -313,6 +313,11 @@ class SkSTArenaAlloc : private std::array<char, InlineStorageSize>, public SkAre
 public:
     explicit SkSTArenaAlloc(size_t firstHeapAllocation = InlineStorageSize)
         : SkArenaAlloc{this->data(), this->size(), firstHeapAllocation} {}
+
+    ~SkSTArenaAlloc() {
+        // Be sure to unpoison the memory that is probably on the stack.
+        sk_asan_unpoison_memory_region(this->data(), this->size());
+    }
 };
 
 template <size_t InlineStorageSize>
@@ -321,6 +326,11 @@ class SkSTArenaAllocWithReset
 public:
     explicit SkSTArenaAllocWithReset(size_t firstHeapAllocation = InlineStorageSize)
             : SkArenaAllocWithReset{this->data(), this->size(), firstHeapAllocation} {}
+
+    ~SkSTArenaAllocWithReset() {
+        // Be sure to unpoison the memory that is probably on the stack.
+        sk_asan_unpoison_memory_region(this->data(), this->size());
+    }
 };
 
 #endif  // SkArenaAlloc_DEFINED