Rename write buffers to store buffers.

src/store-buffer.h

Index: src/store-buffer.h
===================================================================
--- src/store-buffer.h	(revision 6183)
+++ src/store-buffer.h	(working copy)
@@ -39,7 +39,7 @@
 
 // Used to implement the write barrier by collecting addresses of pointers
 // between spaces.
-class WriteBuffer : public AllStatic {
+class StoreBuffer : public AllStatic {
  public:
   static inline Address TopAddress();
 
@@ -48,8 +48,8 @@
 
   static inline void Mark(Address addr);
 
-  static const int kWriteBufferOverflowBit = 1 << 16;
-  static const int kWriteBufferSize = kWriteBufferOverflowBit;
+  static const int kStoreBufferOverflowBit = 1 << 16;
+  static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kHashMapLengthLog2 = 12;
   static const int kHashMapLength = 1 << kHashMapLengthLog2;