| Index: sdk/lib/html/src/Measurement.dart
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| diff --git a/sdk/lib/html/src/Measurement.dart b/sdk/lib/html/src/Measurement.dart
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| deleted file mode 100644
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| index 7d34e7b2db819ea7a865dcc9ef2a3f633e01f8d0..0000000000000000000000000000000000000000
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| --- a/sdk/lib/html/src/Measurement.dart
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| +++ /dev/null
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| @@ -1,200 +0,0 @@
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| -// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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| -// for details. All rights reserved. Use of this source code is governed by a
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| -// BSD-style license that can be found in the LICENSE file.
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| -
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| -part of html;
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| -
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| -typedef Object ComputeValue();
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| -
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| -class _MeasurementRequest<T> {
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| - final ComputeValue computeValue;
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| - final Completer<T> completer;
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| - Object value;
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| - bool exception = false;
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| - _MeasurementRequest(this.computeValue, this.completer);
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| -}
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| -
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| -typedef void _MeasurementCallback();
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| -
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| -/**
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| - * This class attempts to invoke a callback as soon as the current event stack
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| - * unwinds, but before the browser repaints.
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| - */
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| -abstract class _MeasurementScheduler {
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| - bool _nextMeasurementFrameScheduled = false;
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| - _MeasurementCallback _callback;
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| -
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| - _MeasurementScheduler(this._callback);
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| -
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| - /**
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| - * Creates the best possible measurement scheduler for the current platform.
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| - */
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| - factory _MeasurementScheduler.best(_MeasurementCallback callback) {
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| - if (MutationObserver.supported) {
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| - return new _MutationObserverScheduler(callback);
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| - }
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| - return new _PostMessageScheduler(callback);
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| - }
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| -
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| - /**
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| - * Schedules a measurement callback if one has not been scheduled already.
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| - */
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| - void maybeSchedule() {
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| - if (this._nextMeasurementFrameScheduled) {
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| - return;
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| - }
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| - this._nextMeasurementFrameScheduled = true;
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| - this._schedule();
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| - }
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| -
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| - /**
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| - * Does the actual scheduling of the callback.
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| - */
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| - void _schedule();
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| -
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| - /**
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| - * Handles the measurement callback and forwards it if necessary.
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| - */
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| - void _onCallback() {
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| - // Ignore spurious messages.
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| - if (!_nextMeasurementFrameScheduled) {
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| - return;
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| - }
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| - _nextMeasurementFrameScheduled = false;
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| - this._callback();
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| - }
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| -}
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| -
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| -/**
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| - * Scheduler which uses window.postMessage to schedule events.
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| - */
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| -class _PostMessageScheduler extends _MeasurementScheduler {
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| - const _MEASUREMENT_MESSAGE = "DART-MEASURE";
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| -
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| - _PostMessageScheduler(_MeasurementCallback callback): super(callback) {
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| - // Messages from other windows do not cause a security risk as
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| - // all we care about is that _handleMessage is called
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| - // after the current event loop is unwound and calling the function is
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| - // a noop when zero requests are pending.
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| - window.on.message.add(this._handleMessage);
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| - }
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| -
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| - void _schedule() {
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| - window.postMessage(_MEASUREMENT_MESSAGE, "*");
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| - }
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| -
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| - _handleMessage(e) {
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| - this._onCallback();
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| - }
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| -}
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| -
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| -/**
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| - * Scheduler which uses a MutationObserver to schedule events.
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| - */
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| -class _MutationObserverScheduler extends _MeasurementScheduler {
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| - MutationObserver _observer;
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| - Element _dummy;
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| -
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| - _MutationObserverScheduler(_MeasurementCallback callback): super(callback) {
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| - // Mutation events get fired as soon as the current event stack is unwound
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| - // so we just make a dummy event and listen for that.
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| - _observer = new MutationObserver(this._handleMutation);
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| - _dummy = new DivElement();
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| - _observer.observe(_dummy, attributes: true);
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| - }
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| -
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| - void _schedule() {
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| - // Toggle it to trigger the mutation event.
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| - _dummy.hidden = !_dummy.hidden;
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| - }
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| -
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| - _handleMutation(List<MutationRecord> mutations, MutationObserver observer) {
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| - this._onCallback();
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| - }
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| -}
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| -
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| -
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| -List<_MeasurementRequest> _pendingRequests;
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| -List<TimeoutHandler> _pendingMeasurementFrameCallbacks;
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| -_MeasurementScheduler _measurementScheduler = null;
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| -
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| -void _maybeScheduleMeasurementFrame() {
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| - if (_measurementScheduler == null) {
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| - _measurementScheduler =
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| - new _MeasurementScheduler.best(_completeMeasurementFutures);
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| - }
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| - _measurementScheduler.maybeSchedule();
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| -}
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| -
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| -/**
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| - * Registers a [callback] which is called after the next batch of measurements
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| - * completes. Even if no measurements completed, the callback is triggered
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| - * when they would have completed to avoid confusing bugs if it happened that
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| - * no measurements were actually requested.
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| - */
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| -void _addMeasurementFrameCallback(TimeoutHandler callback) {
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| - if (_pendingMeasurementFrameCallbacks == null) {
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| - _pendingMeasurementFrameCallbacks = <TimeoutHandler>[];
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| - _maybeScheduleMeasurementFrame();
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| - }
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| - _pendingMeasurementFrameCallbacks.add(callback);
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| -}
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| -
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| -/**
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| - * Returns a [Future] whose value will be the result of evaluating
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| - * [computeValue] during the next safe measurement interval.
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| - * The next safe measurement interval is after the current event loop has
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| - * unwound but before the browser has rendered the page.
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| - * It is important that the [computeValue] function only queries the html
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| - * layout and html in any way.
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| - */
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| -Future _createMeasurementFuture(ComputeValue computeValue,
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| - Completer completer) {
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| - if (_pendingRequests == null) {
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| - _pendingRequests = <_MeasurementRequest>[];
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| - _maybeScheduleMeasurementFrame();
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| - }
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| - _pendingRequests.add(new _MeasurementRequest(computeValue, completer));
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| - return completer.future;
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| -}
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| -
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| -/**
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| - * Complete all pending measurement futures evaluating them in a single batch
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| - * so that the the browser is guaranteed to avoid multiple layouts.
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| - */
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| -void _completeMeasurementFutures() {
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| - // We must compute all new values before fulfilling the futures as
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| - // the onComplete callbacks for the futures could modify the DOM making
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| - // subsequent measurement calculations expensive to compute.
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| - if (_pendingRequests != null) {
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| - for (_MeasurementRequest request in _pendingRequests) {
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| - try {
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| - request.value = request.computeValue();
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| - } catch (e) {
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| - request.value = e;
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| - request.exception = true;
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| - }
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| - }
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| - }
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| -
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| - final completedRequests = _pendingRequests;
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| - final readyMeasurementFrameCallbacks = _pendingMeasurementFrameCallbacks;
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| - _pendingRequests = null;
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| - _pendingMeasurementFrameCallbacks = null;
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| - if (completedRequests != null) {
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| - for (_MeasurementRequest request in completedRequests) {
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| - if (request.exception) {
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| - request.completer.completeException(request.value);
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| - } else {
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| - request.completer.complete(request.value);
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| - }
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| - }
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| - }
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| -
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| - if (readyMeasurementFrameCallbacks != null) {
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| - for (TimeoutHandler handler in readyMeasurementFrameCallbacks) {
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| - // TODO(jacobr): wrap each call to a handler in a try-catch block.
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| - handler();
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| - }
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| - }
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| -}
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|