chrome/common/page_load_metrics/page_load_metrics.mojom

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module page_load_metrics.mojom;

import "mojo/common/time.mojom";
import "third_party/WebKit/public/platform/web_feature.mojom";

// TimeDeltas below relative to navigation start.
struct DocumentTiming {
  // Time immediately before the DOMContentLoaded event is fired.
  mojo.common.mojom.TimeDelta? dom_content_loaded_event_start;

  // Time immediately before the load event is fired.
  mojo.common.mojom.TimeDelta? load_event_start;

  // Time when the first layout is completed.
  mojo.common.mojom.TimeDelta? first_layout;
};

// TimeDeltas below relative to navigation start.
struct PaintTiming {
  // Time when the first paint is performed.
  mojo.common.mojom.TimeDelta? first_paint;

  // Time when the first non-blank text is painted.
  mojo.common.mojom.TimeDelta? first_text_paint;

  // Time when the first image is painted.
  mojo.common.mojom.TimeDelta? first_image_paint;

  // Time when the first contentful thing (image, text, etc.) is painted.
  mojo.common.mojom.TimeDelta? first_contentful_paint;

  // (Experimental) Time when the page's primary content is painted.
  mojo.common.mojom.TimeDelta? first_meaningful_paint;
};

// TimeDeltas below represent durations of time during the page load.
struct ParseTiming {
  // Time that the document's parser started and stopped parsing main resource
  // content.
  mojo.common.mojom.TimeDelta? parse_start;
  mojo.common.mojom.TimeDelta? parse_stop;

  // Sum of times when the parser is blocked waiting on the load of a script.
  // This duration takes place between parser_start and parser_stop, and thus
  // must be less than or equal to parser_stop - parser_start. Note that this
  // value may be updated multiple times during the period between parse_start
  // and parse_stop.
  mojo.common.mojom.TimeDelta? parse_blocked_on_script_load_duration;

  // Sum of times when the parser is blocked waiting on the load of a script
  // that was inserted from document.write. This duration must be less than or
  // equal to parse_blocked_on_script_load_duration. Note that this value may be
  // updated multiple times during the period between parse_start and
  // parse_stop. Note that some uncommon cases where scripts are loaded via
  // document.write are not currently covered by this field. See crbug/600711
  // for details.
  mojo.common.mojom.TimeDelta? parse_blocked_on_script_load_from_document_write_duration;

  // Sum of times when the parser is executing a script.  This duration takes
  // place between parser_start and parser_stop, and thus must be less than or
  // equal to parser_stop - parser_start. Note that this value may be updated
  // multiple times during the period between parse_start and parse_stop.
  mojo.common.mojom.TimeDelta? parse_blocked_on_script_execution_duration;

  // Sum of times when the parser is executing a script that was inserted from
  // document.write. This duration must be less than or equal to
  // parse_blocked_on_script_load_duration. Note that this value may be updated
  // multiple times during the period between parse_start and parse_stop. Note
  // that some uncommon cases where scripts are loaded via document.write are
  // not currently covered by this field. See crbug/600711 for details.
  mojo.common.mojom.TimeDelta? parse_blocked_on_script_execution_from_document_write_duration;
};

struct StyleSheetTiming {
  // Total time spent parsing author style sheets, before the first contentful
  // paint.
  mojo.common.mojom.TimeDelta? author_style_sheet_parse_duration_before_fcp;
  // Time spent in Document::updateStyle before FCP.
  mojo.common.mojom.TimeDelta? update_style_duration_before_fcp;
};

// PageLoadTiming contains timing metrics associated with a page load. Many of
// the metrics here are based on the Navigation Timing spec:
// http://www.w3.org/TR/navigation-timing/.
struct PageLoadTiming {
  // Time that the navigation for the associated page was initiated. Note that
  // this field is only used for internal tracking purposes and should not be
  // used by PageLoadMetricsObservers. This field will likely be removed in the
  // future.
  mojo.common.mojom.Time navigation_start;

  // Time relative to navigation_start that the first byte of the response is
  // received.
  mojo.common.mojom.TimeDelta? response_start;
  DocumentTiming document_timing;
  PaintTiming paint_timing;
  ParseTiming parse_timing;
  StyleSheetTiming style_sheet_timing;

  // If you add additional members, also be sure to update page_load_timing.h.
};

struct PageLoadMetadata {
  // These are packed blink::WebLoadingBehaviorFlag enums.
  int32 behavior_flags = 0;
};

// PageLoadFeatures contains a list of features newly observed by use counter.
// In a given page load, no PageLoadFeatures sent will contain previously seen
// values.
struct PageLoadFeatures {
  // These features are defined as blink::mojom::WebFeature enums.
  array<blink.mojom.WebFeature> features;
};

// Sent from renderer to browser process when the PageLoadTiming for the
// associated frame changed.
interface PageLoadMetrics {
  UpdateTiming(PageLoadTiming page_load_timing,
               PageLoadMetadata page_load_metadata,
               PageLoadFeatures new_features);
};