Oilpan: Reduce the reserved size of CallbackStacks

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

Index: third_party/WebKit/Source/platform/heap/CallbackStack.cpp
diff --git a/third_party/WebKit/Source/platform/heap/CallbackStack.cpp b/third_party/WebKit/Source/platform/heap/CallbackStack.cpp
index 48823846abdabb8d8e30471327d1629f12560ac8..ad04cd74563d1eac6403ed8b8eed319ad53a5da7 100644
--- a/third_party/WebKit/Source/platform/heap/CallbackStack.cpp
+++ b/third_party/WebKit/Source/platform/heap/CallbackStack.cpp
@@ -3,9 +3,29 @@
 // found in the LICENSE file.
 
 #include "platform/heap/CallbackStack.h"
+#include "wtf/Partitions.h"
 
 namespace blink {
 
+CallbackStack::Block::Block(Block* next, size_t blockSize)
+    : m_blockSize(blockSize)
+{
+    m_buffer = static_cast<Item*>(WTF::Partitions::fastMalloc(blockSize * sizeof(Item), "CallbackStack::Block"));
+    m_limit = &(m_buffer[m_blockSize]);
+    m_current = &(m_buffer[0]);
+    m_next = next;
+    clearUnused();
+}
+
+CallbackStack::Block::~Block()
+{
+    clearUnused();
+    m_limit = nullptr;
+    m_current = nullptr;
+    m_next = nullptr;
+    WTF::Partitions::fastFree(m_buffer);
+}
+
 void CallbackStack::Block::clear()
 {
     m_current = &m_buffer[0];
@@ -38,12 +58,14 @@ bool CallbackStack::Block::hasCallbackForObject(const void* object)
 void CallbackStack::Block::clearUnused()
 {
 #if ENABLE(ASSERT)
-    for (size_t i = 0; i < blockSize; i++)
+    for (size_t i = 0; i < m_blockSize; i++)
         m_buffer[i] = Item(0, 0);
 #endif
 }
 
-CallbackStack::CallbackStack() : m_first(new Block(0)), m_last(m_first)
+CallbackStack::CallbackStack(size_t reservedStackSize)
+    : m_first(new Block(nullptr, reservedStackSize))
+    , m_last(m_first)
 {
 }
 
@@ -74,7 +96,7 @@ bool CallbackStack::isEmpty() const
 CallbackStack::Item* CallbackStack::allocateEntrySlow()
 {
     ASSERT(!m_first->allocateEntry());
-    m_first = new Block(m_first);
+    m_first = new Block(m_first, m_first->blockSize() * 2);
     return m_first->allocateEntry();
 }