Oilpan: Don't use guard pages in NaCl

Source/platform/heap/PageMemory.h

Index: Source/platform/heap/PageMemory.h
diff --git a/Source/platform/heap/PageMemory.h b/Source/platform/heap/PageMemory.h
index f81703704d80a94a49723981a85df639b1c18ab3..70f5f4b65e829c3457ea78012f397641fff33bf4 100644
--- a/Source/platform/heap/PageMemory.h
+++ b/Source/platform/heap/PageMemory.h
@@ -5,6 +5,7 @@
 #ifndef PageMemory_h
 #define PageMemory_h
 
+#include "platform/heap/Heap.h"
 #include "wtf/Assertions.h"
 #include "wtf/PageAllocator.h"
 
@@ -203,9 +204,8 @@ public:
 
     static PageMemory* setupPageMemoryInRegion(PageMemoryRegion* region, size_t pageOffset, size_t payloadSize)
     {
-        // Setup the payload one OS page into the page memory. The
-        // first os page is the guard page.
-        Address payloadAddress = region->base() + pageOffset + WTF::kSystemPageSize;
+        // Setup the payload one guard page into the page memory.
+        Address payloadAddress = region->base() + pageOffset + blinkGuardPageSize;
         return new PageMemory(region, MemoryRegion(payloadAddress, payloadSize));
     }
 
@@ -227,7 +227,7 @@ public:
 
         // Overallocate by 2 times OS page size to have space for a
         // guard page at the beginning and end of blink heap page.
-        size_t allocationSize = payloadSize + 2 * WTF::kSystemPageSize;
+        size_t allocationSize = payloadSize + 2 * blinkGuardPageSize;
         PageMemoryRegion* pageMemoryRegion = PageMemoryRegion::allocateLargePage(allocationSize);
         PageMemory* storage = setupPageMemoryInRegion(pageMemoryRegion, 0, payloadSize);
         RELEASE_ASSERT(storage->commit());