Large source maps throwing errors

Debugging huge 4+ MB bundles with source maps is causing some issues with DevTools.

`build.js`

``` js
require('browserify')('index.js', { debug: true })
.bundle(function (err, src) {
if (err) throw err
console.log(src.length)
})
```

`index.js`

``` js
require('three');
require('babel-polyfill');
require('react');
require('react-dom');
```

Lots of errors like these appear in console:

``` txt
[36291:0119/224251:ERROR:CONSOLE(1381)] "NetworkError: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIm5vZGVfbW9kdWxlcy9yZWFjdC9saWIvUmVhY3RET00uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IjtBQUFBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7...BsaXQsIFN0cmluZy5wcm90b3R5cGUudHJpbSxcblxuICAgIC8vIHNoYW1zXG4gICAgT2JqZWN0LmNyZWF0ZSwgT2JqZWN0LmZyZWV6ZV07XG5cbiAgICBmb3IgKHZhciBpID0gMDsgaSA8IGV4cGVjdGVkRmVhdHVyZXMubGVuZ3RoOyBpKyspIHtcbiAgICAgIGlmICghZXhwZWN0ZWRGZWF0dXJlc1tpXSkge1xuICAgICAgICBjb25zb2xlLmVycm9yKCdPbmUgb3IgbW9yZSBFUzUgc2hpbS9zaGFtcyBleHBlY3RlZCBieSBSZWFjdCBhcmUgbm90IGF2YWlsYWJsZTogJyArICdodHRwczovL2ZiLm1lL3JlYWN0LXdhcm5pbmctcG9seWZpbGxzJyk7XG4gICAgICAgIGJyZWFrO1xuICAgICAgfVxuICAgIH1cbiAgfVxufVxuXG5tb2R1bGUuZXhwb3J0cyA9IFJlYWN0OyJdfQ==})()'. Error: Failed to execute 'send' on 'XMLHttpRequest': Failed to load 'data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbIm5vZGVfbW9kdWxlcy9yZWFjdC9saWIvUmVhY3RET00uanMiXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IjtBQUFBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7QUFDQTtBQUNBO0FBQ0E7...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})()'.
at Error (native)
at Function.WebInspector.SourceMap.load (chrome-devtools://devtools/bundled/inspector.js:6392:151)
at Object.WebInspector.CompilerScriptMapping._loadSourceMapForScript (chrome-devtools://devtools/bundled/inspector.js:7186:122)
at Object.WebInspector.CompilerScriptMapping._processScript (chrome-devtools://devtools/bundled/inspector.js:7164:663)
at Object.WebInspector.CompilerScriptMapping.addScript (chrome-devtools://devtools/bundled/inspector.js:7161:6)
at Object.WebInspector.DebuggerWorkspaceBinding.TargetData._parsedScriptSource (chrome-devtools://devtools/bundled/inspector.js:7540:23)
at Object.WebInspector.Object.dispatchEventToListeners (chrome-devtools://devtools/bundled/inspector.js:748:185)
at Object.WebInspector.DebuggerModel._parsedScriptSource (chrome-devtools://devtools/bundled/inspector.js:5102:6)
at Object.WebInspector.DebuggerDispatcher.scriptFailedToParse (chrome-devtools://devtools/bundled/inspector.js:5163:22)
at Object.InspectorBackendClass.DispatcherPrototype.dispatch (chrome-devtools://devtools/bundled/inspector.js:3913:63)", source: chrome-devtools://devtools/bundled/inspector.js (1381)
```