Oilpan: Decommit backing storage of CallbackStacks

third_party/WebKit/Source/platform/heap/Heap.cpp

Index: third_party/WebKit/Source/platform/heap/Heap.cpp
diff --git a/third_party/WebKit/Source/platform/heap/Heap.cpp b/third_party/WebKit/Source/platform/heap/Heap.cpp
index eed2697b77f65c834c1b126ac137bb15a1f228bd..97b11121b20e86612ec9f0372041c5b271146f78 100644
--- a/third_party/WebKit/Source/platform/heap/Heap.cpp
+++ b/third_party/WebKit/Source/platform/heap/Heap.cpp
@@ -304,6 +304,14 @@ bool Heap::weakTableRegistered(const void* table)
 }
 #endif
 
+void Heap::decommitCallbackStacks()
+{
+    s_markingStack->decommit();
+    s_postMarkingCallbackStack->decommit();
+    s_globalWeakCallbackStack->decommit();
+    s_ephemeronStack->decommit();
+}
+
 void Heap::preGC()
 {
     ASSERT(!ThreadState::current()->isInGC());
@@ -420,6 +428,7 @@ void Heap::collectGarbage(BlinkGC::StackState stackState, BlinkGC::GCType gcType
     WTF::Partitions::reportMemoryUsageHistogram();
 
     postGC(gcType);
+    Heap::decommitCallbackStacks();
 
 #if ENABLE(ASSERT)
     // 0 is used to figure non-assigned area, so avoid to use 0 in s_gcGeneration.
@@ -462,6 +471,7 @@ void Heap::collectGarbageForTerminatingThread(ThreadState* state)
         globalWeakProcessing(visitorScope.visitor());
 
         state->postGC(BlinkGC::GCWithSweep);
+        Heap::decommitCallbackStacks();
     }
     state->preSweep();
 }
@@ -498,8 +508,6 @@ void Heap::postMarkingProcessing(Visitor* visitor)
     //    if they are only reachable from their front objects.
     while (popAndInvokePostMarkingCallback(visitor)) { }
 
-    s_ephemeronStack->clear();
-
     // Post-marking callbacks should not trace any objects and
     // therefore the marking stack should be empty after the
     // post-marking callbacks.