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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/sessions/tab_loader_delegate.h"
#include "base/functional/bind.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "base/strings/string_number_conversions.h"
#include "chrome/browser/resource_coordinator/session_restore_policy.h"
#include "chrome/browser/resource_coordinator/tab_manager_features.h"
#include "chrome/browser/sessions/session_restore_observer.h"
#include "components/variations/variations_associated_data.h"
#include "content/public/browser/network_service_instance.h"
#include "services/network/public/cpp/network_connection_tracker.h"
namespace {
// The timeout time after which the next tab gets loaded if the previous tab did
// not finish loading yet. The used value is half of the median value of all
// ChromeOS devices loading the 25 most common web pages. Half is chosen since
// the loading time is a mix of server response and data bandwidth.
static const int kInitialDelayTimerMS = 1500;
// Similar to the above constant, but the timeout that is afforded to the
// visible tab only. Having this be a longer value ensures the visible time has
// more time during which it is the only one loading, decreasing the time to
// first paint and interactivity of the foreground tab.
static const int kFirstTabLoadTimeoutMS = 60000;
resource_coordinator::SessionRestorePolicy* g_testing_policy = nullptr;
class TabLoaderDelegateImpl
: public TabLoaderDelegate,
public network::NetworkConnectionTracker::NetworkConnectionObserver {
public:
explicit TabLoaderDelegateImpl(TabLoaderCallback* callback);
TabLoaderDelegateImpl(const TabLoaderDelegateImpl&) = delete;
TabLoaderDelegateImpl& operator=(const TabLoaderDelegateImpl&) = delete;
~TabLoaderDelegateImpl() override;
// TabLoaderDelegate:
base::TimeDelta GetFirstTabLoadingTimeout() const override {
return resource_coordinator::GetTabLoadTimeout(first_timeout_);
}
// TabLoaderDelegate:
base::TimeDelta GetTimeoutBeforeLoadingNextTab() const override {
return resource_coordinator::GetTabLoadTimeout(timeout_);
}
// TabLoaderDelegate:
size_t GetMaxSimultaneousTabLoads() const override {
return policy_->simultaneous_tab_loads();
}
// TabLoaderDelegate:
float AddTabForScoring(content::WebContents* contents) const override {
return policy_->AddTabForScoring(contents);
}
// TabLoaderDelegate:
void RemoveTabForScoring(content::WebContents* contents) const override {
policy_->RemoveTabForScoring(contents);
}
// TabLoaderDelegate:
bool ShouldLoad(content::WebContents* contents) const override {
return policy_->ShouldLoad(contents);
}
// TabLoaderDelegate:
void NotifyTabLoadStarted() override { policy_->NotifyTabLoadStarted(); }
// TabLoaderDelegate:
resource_coordinator::SessionRestorePolicy* GetPolicyForTesting() override {
return policy_;
}
// network::NetworkConnectionTracker::NetworkConnectionObserver:
void OnConnectionChanged(network::mojom::ConnectionType type) override;
// Callback that is invoked by the policy engine, and forwarded over to the
// TabLoader.
void NotifyTabScoreChanged(content::WebContents* content, float score);
private:
// The default policy engine used to implement ShouldLoad.
resource_coordinator::SessionRestorePolicy default_policy_;
// The policy engine used to implement ShouldLoad. By default this is simply
// a pointer to |default_policy_|, but it can also point to externally
// injected policy engine for testing.
raw_ptr<resource_coordinator::SessionRestorePolicy> policy_;
// The function to call when the connection type changes.
raw_ptr<TabLoaderCallback> callback_;
// The timeouts to use in tab loading.
base::TimeDelta first_timeout_;
base::TimeDelta timeout_;
base::WeakPtrFactory<TabLoaderDelegateImpl> weak_factory_{this};
};
TabLoaderDelegateImpl::TabLoaderDelegateImpl(TabLoaderCallback* callback)
: policy_(&default_policy_), callback_(callback) {
content::GetNetworkConnectionTracker()->AddNetworkConnectionObserver(this);
auto type = network::mojom::ConnectionType::CONNECTION_UNKNOWN;
content::GetNetworkConnectionTracker()->GetConnectionType(
&type, base::BindOnce(&TabLoaderDelegateImpl::OnConnectionChanged,
weak_factory_.GetWeakPtr()));
if (type == network::mojom::ConnectionType::CONNECTION_NONE) {
// When we are off-line we do not allow loading of tabs, since each of
// these tabs would start loading simultaneously when going online.
// TODO(skuhne): Once we get a higher level resource control logic which
// distributes network access, we can remove this.
callback->SetTabLoadingEnabled(false);
}
first_timeout_ = base::Milliseconds(kFirstTabLoadTimeoutMS);
timeout_ = base::Milliseconds(kInitialDelayTimerMS);
// Override |policy_| if a testing policy has been set.
if (g_testing_policy) {
policy_ = g_testing_policy;
}
// Register the policy callback.
policy_->SetTabScoreChangedCallback(
base::BindRepeating(&TabLoaderDelegateImpl::NotifyTabScoreChanged,
weak_factory_.GetWeakPtr()));
}
TabLoaderDelegateImpl::~TabLoaderDelegateImpl() {
content::GetNetworkConnectionTracker()->RemoveNetworkConnectionObserver(this);
}
void TabLoaderDelegateImpl::OnConnectionChanged(
network::mojom::ConnectionType type) {
callback_->SetTabLoadingEnabled(
type != network::mojom::ConnectionType::CONNECTION_NONE);
}
void TabLoaderDelegateImpl::NotifyTabScoreChanged(content::WebContents* content,
float score) {
callback_->NotifyTabScoreChanged(content, score);
}
} // namespace
// static
std::unique_ptr<TabLoaderDelegate> TabLoaderDelegate::Create(
TabLoaderCallback* callback) {
return std::unique_ptr<TabLoaderDelegate>(
new TabLoaderDelegateImpl(callback));
}
// static
void TabLoaderDelegate::SetSessionRestorePolicyForTesting(
resource_coordinator::SessionRestorePolicy* policy) {
g_testing_policy = policy;
}
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