Previously, this threw:
```
FAIL src/test/__tests__/ReactTestUtils-test.js (7.291s)
● ReactTestUtils › it can fail context when shallowly rendering
- TypeError: Cannot read property '_source' of null
at describeID (src/renderers/shared/devtools/ReactComponentTreeDevtool.js:70:46)
at Object.ReactComponentTreeDevtool.getStackAddendumByID (src/renderers/shared/devtools/ReactComponentTreeDevtool.js:203:15)
at checkReactTypeSpec (src/isomorphic/classic/types/checkReactTypeSpec.js:76:58)
at ReactCompositeComponentMixin._checkContextTypes (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:668:5)
at ReactCompositeComponentMixin._processContext (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:607:14)
at ReactCompositeComponentMixin.mountComponent (src/renderers/shared/stack/reconciler/ReactCompositeComponent.js:191:30)
at ReactShallowRenderer._render (src/test/ReactTestUtils.js:483:14)
at _batchedRender (src/test/ReactTestUtils.js:460:12)
at ReactDefaultBatchingStrategyTransaction.Mixin.perform (src/shared/utils/Transaction.js:140:20)
at Object.ReactDefaultBatchingStrategy.batchedUpdates (src/renderers/shared/stack/reconciler/ReactDefaultBatchingStrategy.js:65:19)
at Object.batchedUpdates (src/renderers/shared/stack/reconciler/ReactUpdates.js:112:20)
at ReactShallowRenderer.render (src/test/ReactTestUtils.js:453:16)
at Spec.eval (src/test/__tests__/ReactTestUtils-test.js:289:34)
at jasmine.Block.execute (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:1067:17)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2100:31)
at jasmine.Queue.start (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2053:8)
at Spec.jasmine.Spec.execute (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2380:14)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2100:31)
at onComplete (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2096:18)
at Spec.jasmine.Spec.finish (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2354:5)
at eval [as onComplete] (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2381:10)
at jasmine.Queue.next_ (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2110:14)
at eval (node_modules/jest-jasmine1/vendor/jasmine-1.3.0.js:2090:18)
at Timeout.e [as _onTimeout] (node_modules/jsdom/lib/jsdom/browser/Window.js:440:19)
at tryOnTimeout (timers.js:224:11)
at Timer.listOnTimeout (timers.js:198:5)
```
This adds some tests for getElement() and verifies that it works for text components too.
The code that calls the instrumentation is fixed where necessary so that the tests pass.
We extract common logic between DOM and native tests so they don't diverge.
Also, rather than build a tree object in advance for testing, we will walk the tree on the go.
This lets us have much more specific error messages with a clear path when something goes wrong.
For clarity.
I left "native event" as-is because there's a lot of it, it's not particularly ambiguous, and SimulateNative/nativeTouchData are public API in ReactTestUtils.
This makes it easier to figure out where the docs live.
Googling for e.g. `react-addons-update` also works, but this should
make things easier for people that hyperclick directly to the source.
ReactDOMInput and a few other classes handle change event by scheduling updateWrapper() in an asap().
It gets executed after the batch, which confuses ReactPerf that expects all DOM writes to happen during a batch.
Since this implementation of ReactPerf relying on the stack is going away, let's plug the hole temporarily by ignoring DOM writes that occur during postponed updateWrapper(). In any case, they have no relation to actual calculations of wasted renders, as they don't occur due to updateComponent(), but rather due to onChange() special DOM behavior.
This fixes#5548
We intend to change the measurement format significantly in #6046. In order to introduce the new ReactPerf during 15.x release cycle, we are making the measurement structure opaque-ish in 15.0.
This is a little simpler (and a teeny tiny bit faster). The one in ReactCompositeComponent stays because of the way we create ReactCompositeComponentWrapper inside instantiateReactComponent.