Add support for startup data (snapshot) compression.

src/snapshot-common.cc

Index: src/snapshot-common.cc
diff --git a/src/snapshot-common.cc b/src/snapshot-common.cc
index 7f82895802db2e9bee043f2ef3c38d5c43ed27cf..227f6357dd85090ca0b81433a7dd5a555d26e82f 100644
--- a/src/snapshot-common.cc
+++ b/src/snapshot-common.cc
@@ -53,7 +53,7 @@ bool Snapshot::Initialize(const char* snapshot_file) {
     DeleteArray(str);
     return true;
   } else if (size_ > 0) {
-    Deserialize(data_, size_);
+    Deserialize(decompressed_data_, decompressed_size_);
     return true;
   }
   return false;
@@ -71,7 +71,8 @@ Handle<Context> Snapshot::NewContextFromSnapshot() {
                      map_space_used_,
                      cell_space_used_,
                      large_space_used_);
-  SnapshotByteSource source(context_data_, context_size_);
+  SnapshotByteSource source(context_decompressed_data_,
+                            context_decompressed_size_);
   Deserializer deserializer(&source);
   Object* root;
   deserializer.DeserializePartial(&root);