Add some support for promptly purging pages.

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

Index: third_party/WebKit/Source/platform/heap/PagePool.cpp
diff --git a/third_party/WebKit/Source/platform/heap/PagePool.cpp b/third_party/WebKit/Source/platform/heap/PagePool.cpp
index 4af09bca1f2a2890e6c3ca6a1c7a4e1694b6c0d8..e81b6141bc18fd13dd130f43af9795d807cdd8c5 100644
--- a/third_party/WebKit/Source/platform/heap/PagePool.cpp
+++ b/third_party/WebKit/Source/platform/heap/PagePool.cpp
@@ -28,11 +28,13 @@ PagePool::~PagePool() {
   }
 }
 
-void PagePool::Add(int index, PageMemory* memory) {
+void PagePool::Add(int index,
+                   PageMemory* memory,
+                   DecommitMemoryTiming decommit_hint) {
   // When adding a page to the pool we decommit it to ensure it is unused
   // while in the pool.  This also allows the physical memory, backing the
   // page, to be given back to the OS.
-  memory->Decommit();
+  memory->Decommit(decommit_hint);
   PoolEntry* entry = new PoolEntry(memory, pool_[index]);
   pool_[index] = entry;
 }