Tree shaker:

runtime/vm/object.h

Index: runtime/vm/object.h
diff --git a/runtime/vm/object.h b/runtime/vm/object.h
index 2cbd331ace2c25433c19b3c2a2a68a16c01cde46..41593d66201e1b7feb8d561b39bf8c1e9d73e0c8 100644
--- a/runtime/vm/object.h
+++ b/runtime/vm/object.h
@@ -3764,7 +3764,6 @@ class Library : public Object {
   void AddClass(const Class& cls) const;
   void AddObject(const Object& obj, const String& name) const;
   void ReplaceObject(const Object& obj, const String& name) const;
-  bool RemoveObject(const Object& obj, const String& name) const;
   RawObject* LookupReExport(const String& name,
                             ZoneGrowableArray<intptr_t>* visited = NULL) const;
   RawObject* LookupObjectAllowPrivate(const String& name) const;
@@ -3827,7 +3826,7 @@ class Library : public Object {
   RawLibrary* ImportLibraryAt(intptr_t index) const;
   bool ImportsCorelib() const;
 
-  void DropDependencies() const;
+  void DropDependenciesAndCaches() const;
 
   // Resolving native methods for script loaded in the library.
   Dart_NativeEntryResolver native_entry_resolver() const {
@@ -3962,7 +3961,7 @@ class Library : public Object {
 
 
   void InitImportList() const;
-  void GrowDictionary(const Array& dict, intptr_t dict_size) const;
+  void RehashDictionary(const Array& old_dict, intptr_t new_dict_size) const;
   static RawLibrary* NewLibraryHelper(const String& url, bool import_core_lib);
   RawObject* LookupEntry(const String& name, intptr_t* index) const;
 
@@ -3980,11 +3979,12 @@ class Library : public Object {
   friend class Bootstrap;
   friend class Class;
   friend class Debugger;
-  friend class Isolate;
   friend class DictionaryIterator;
+  friend class Isolate;
+  friend class LibraryDeserializationCluster;
   friend class Namespace;
   friend class Object;
-  friend class LibraryDeserializationCluster;
+  friend class Precompiler;
 };