[serializer] split up src/snapshot/serialize.*

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index e19dd104eb9c0e7939e93015761cd633e0290c7e..5306d8759da4a222e2d023beecfb201ed2001eb4 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -704,6 +704,7 @@ source_set("v8_base") {
     "src/code-stubs-hydrogen.cc",
     "src/codegen.cc",
     "src/codegen.h",
+    "src/collector.h",
     "src/compilation-cache.cc",
     "src/compilation-cache.h",
     "src/compilation-dependencies.cc",
@@ -1282,13 +1283,23 @@ source_set("v8_base") {
     "src/signature.h",
     "src/simulator.h",
     "src/small-pointer-list.h",
+    "src/snapshot/code-serializer.cc",
+    "src/snapshot/code-serializer.h",
+    "src/snapshot/deserializer.cc",
+    "src/snapshot/deserializer.h",
     "src/snapshot/natives.h",
     "src/snapshot/natives-common.cc",
-    "src/snapshot/serialize.cc",
-    "src/snapshot/serialize.h",
+    "src/snapshot/partial-serializer.cc",
+    "src/snapshot/partial-serializer.h",
+    "src/snapshot/serializer.cc",
+    "src/snapshot/serializer.h",
+    "src/snapshot/serializer-common.cc",
+    "src/snapshot/serializer-common.h",
     "src/snapshot/snapshot-common.cc",
     "src/snapshot/snapshot-source-sink.cc",
     "src/snapshot/snapshot-source-sink.h",
+    "src/snapshot/startup-serializer.cc",
+    "src/snapshot/startup-serializer.h",
     "src/source-position.h",
     "src/splay-tree.h",
     "src/splay-tree-inl.h",