chromium/third_party/blink/renderer/core/html/lazy_load_frame_observer.cc

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "third_party/blink/renderer/core/html/lazy_load_frame_observer.h"

#include <limits>

#include "base/trace_event/trace_event.h"
#include "third_party/blink/public/platform/web_effective_connection_type.h"
#include "third_party/blink/renderer/core/dom/document.h"
#include "third_party/blink/renderer/core/dom/node_computed_style.h"
#include "third_party/blink/renderer/core/frame/frame.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_client.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/html/html_frame_owner_element.h"
#include "third_party/blink/renderer/core/html/loading_attribute.h"
#include "third_party/blink/renderer/core/intersection_observer/intersection_observer.h"
#include "third_party/blink/renderer/core/intersection_observer/intersection_observer_entry.h"
#include "third_party/blink/renderer/core/loader/frame_load_request.h"
#include "third_party/blink/renderer/core/loader/frame_loader.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
#include "third_party/blink/renderer/platform/geometry/length.h"
#include "third_party/blink/renderer/platform/loader/fetch/resource_request.h"
#include "third_party/blink/renderer/platform/network/network_state_notifier.h"
#include "third_party/blink/renderer/platform/weborigin/security_origin.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"

namespace blink {

namespace {

// Determine if the |bounding_client_rect| for a frame indicates that the frame
// is probably hidden according to some experimental heuristics. Since hidden
// frames are often used for analytics or communication, and lazily loading them
// could break their functionality, so these heuristics are used to recognize
// likely hidden frames and immediately load them so that they can function
// properly.
bool IsFrameProbablyHidden(const gfx::RectF& bounding_client_rect,
                           const Element& element) { … }

int GetLazyLoadingFrameMarginPx(const Document& document) { … }

}  // namespace

struct LazyLoadFrameObserver::LazyLoadRequestInfo { … };

LazyLoadFrameObserver::LazyLoadFrameObserver(HTMLFrameOwnerElement& element,
                                             LoadType load_type)
    : … { … }

LazyLoadFrameObserver::~LazyLoadFrameObserver() = default;

void LazyLoadFrameObserver::DeferLoadUntilNearViewport(
    const ResourceRequestHead& resource_request,
    WebFrameLoadType frame_load_type) { … }

void LazyLoadFrameObserver::CancelPendingLazyLoad() { … }

void LazyLoadFrameObserver::LoadIfHiddenOrNearViewport(
    const HeapVector<Member<IntersectionObserverEntry>>& entries) { … }

void LazyLoadFrameObserver::LoadImmediately() { … }

void LazyLoadFrameObserver::Trace(Visitor* visitor) const { … }

}  // namespace blink