Add GrowableObjectArray::ToUserCString().

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 31037)
+++ runtime/vm/object.h	(working copy)
@@ -3964,7 +3964,11 @@
 
   // Returns a string representation of this instance in a form
   // that is suitable for an end user.
-  virtual const char* ToUserCString(intptr_t maxLen = 40) const;
+  //
+  // max_len is advisory, and the returned string may exceed this max
+  // length.
+  virtual const char* ToUserCString(intptr_t max_len = 40,
+                                    intptr_t nesting = 0) const;
 
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawInstance));
@@ -4899,7 +4903,8 @@
                           Dart_PeerFinalizer cback) const;
 
   // Produces a quoted, escaped, (possibly) truncated string.
-  const char* ToUserCString(intptr_t maxLen = 40) const;
+  const char* ToUserCString(intptr_t max_len = 40,
+                            intptr_t nesting = 0) const;
 
   // Creates a new String object from a C string that is assumed to contain
   // UTF-8 encoded characters and '\0' is considered a termination character.
@@ -5025,7 +5030,7 @@
                            CallbackType new_symbol,
                            Snapshot::Kind kind);
 
-  intptr_t EscapedString(char* buffer, int maxLen) const;
+  intptr_t EscapedString(char* buffer, int max_len) const;
   intptr_t EscapedStringLen(intptr_t tooLong) const;
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(String, Instance);
@@ -5627,6 +5632,11 @@
     return Instance::null();
   }
 
+  // Produces a readable representation of this array, e.g. '[1,2,3]',
+  // subject to length limits.
+  const char* ToUserCString(intptr_t max_len = 40,
+                            intptr_t nesting = 0) const;
+
   static intptr_t type_arguments_offset() {
     return OFFSET_OF(RawGrowableObjectArray, type_arguments_);
   }