Manually default Error messages to avoid dart2js code bloat.

sdk/lib/core/errors.dart

Index: sdk/lib/core/errors.dart
diff --git a/sdk/lib/core/errors.dart b/sdk/lib/core/errors.dart
index f4509eb774968ed67531c05c56d03ee31c75ab07..75cac23585cf7f25dc540c39f663a650a93e3062 100644
--- a/sdk/lib/core/errors.dart
+++ b/sdk/lib/core/errors.dart
@@ -243,9 +243,9 @@ class RangeError extends ArgumentError {
       : invalidValue = null, start = null, end = null, super(message);
 
   /** Create a new [RangeError] with a message for the given [value]. */
-  RangeError.value(num value, [String message = "Value not in range"])
+  RangeError.value(num value, [String message])
       : invalidValue = value, start = null, end = null,
-        super(message);
+        super(message != null ? message : "Value not in range");
 
   /**
    * Create a new [RangeError] with for an invalid value being outside a range.
@@ -256,8 +256,8 @@ class RangeError extends ArgumentError {
    * For a range from 0 to the length of something, end exclusive, use
    * [RangeError.index].
    */
-  RangeError.range(this.invalidValue, this.start, this.end,
-                   [String message = "Invalid value"]) : super(message);
+  RangeError.range(this.invalidValue, this.start, this.end, [String message])
+      : super(message != null ? message : "Invalid value");
 
   /**
    * Creates a new [RangeError] stating that [index] is not a valid index
@@ -317,11 +317,10 @@ class IndexError extends ArgumentError implements RangeError {
    *
    * The message is used as part of the string representation of the error.
    */
-  IndexError(this.invalidValue, indexable,
-             [String message = "Index out of range", int length])
+  IndexError(this.invalidValue, indexable, [String message, int length])
       : this.indexable = indexable,
         this.length = (length != null) ? length : indexable.length,
-        super(message);
+        super(message != null ? message : "Index out of range");
 
   // Getters inherited from RangeError.
   int get start => 0;