Inline source maps as part of each script.

pkg/dev_compiler/lib/src/compiler/compiler.dart

Index: pkg/dev_compiler/lib/src/compiler/compiler.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/compiler.dart b/pkg/dev_compiler/lib/src/compiler/compiler.dart
index 93389ab2f94fa20b4694ef25cfc671cf8c2f56ca..332ec6b43c99b90cff9dd71b5810eaf77509439a 100644
--- a/pkg/dev_compiler/lib/src/compiler/compiler.dart
+++ b/pkg/dev_compiler/lib/src/compiler/compiler.dart
@@ -509,12 +509,18 @@ class JSModuleFile {
     }
 
     var text = printer.getText();
-    var rawSourceMap = options.inlineSourceMap ? JSON.encode(builtMap) : null;
+    var rawSourceMap = 'null';
+    if (options.inlineSourceMap) {
+      var bytes = UTF8.encode(JSON.encode(builtMap));
+      // Base64 encode instead of json escaping to work around V8 bug
+      // unescaping strings with a large number of slashes.
+      rawSourceMap = "'${BASE64.encode(bytes)}'";
+    }
     // Encode the sourcemap as an escaped string rather than JSON
     // as Dart code using the sourcemap can't take advantage of it being JS
     // JSON so we might as well encode it as a String which should be quicker
     // to parse.
-    text = text.replaceFirst(sourceMapHoleID, JSON.encode(rawSourceMap));
+    text = text.replaceFirst(sourceMapHoleID, rawSourceMap);
 
     return new JSModuleCode(text, builtMap);
   }