Add a first class GrowableObjectArray type in the VM and use it internally in the VM at all spots w…

vm/raw_object.h

Index: vm/raw_object.h
===================================================================
--- vm/raw_object.h	(revision 5060)
+++ vm/raw_object.h	(working copy)
@@ -61,6 +61,7 @@
     V(Bool)                                                                    \
     V(Array)                                                                   \
       V(ImmutableArray)                                                        \
+    V(GrowableObjectArray)                                                     \
     V(ByteArray)                                                               \
       V(InternalByteArray)                                                     \
       V(ExternalByteArray)                                                     \
@@ -986,6 +987,7 @@
 
   friend class RawImmutableArray;
   friend class SnapshotReader;
+  friend class GrowableObjectArray;
 };
 
 
@@ -996,6 +998,22 @@
 };
 
 
+class RawGrowableObjectArray : public RawInstance {
+  RAW_HEAP_OBJECT_IMPLEMENTATION(GrowableObjectArray);
+
+  RawObject** from() {
+    return reinterpret_cast<RawObject**>(&ptr()->data_);
+  }
+  RawSmi* length_;
+  RawArray* data_;
+  RawObject** to() {
+    return reinterpret_cast<RawObject**>(&ptr()->data_);
+  }
+
+  friend class SnapshotReader;
+};
+
+
 class RawByteArray : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(ByteArray);