
This helper was created in
commit 7b509e56dc
to expedite the UI/IO
thread simplification effort, and particularly the service worker thread
migration which is now complete. It was not intended as a long-term
function for general use, as it is a strange layer over the normal
threading and tasks functions in base/ and encourages a typically
unrecommended pattern of "maybe async, maybe sync". There are just a
few targeted uses of it today, and these can directly use the usual
functions without this helper.
Bug: 1138155, 1187753
Change-Id: I7c82f0909656a802ec103b2af40bceb436e26e57
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3173372
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Martin Šrámek <msramek@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/main@{#924711}
133 lines
4.5 KiB
C++
133 lines
4.5 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "content/browser/field_trial_synchronizer.h"
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#include "base/bind.h"
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#include "base/check_op.h"
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#include "base/threading/thread.h"
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#include "components/metrics/persistent_system_profile.h"
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#include "components/variations/variations_client.h"
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#include "content/common/renderer_variations_configuration.mojom.h"
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#include "content/public/browser/browser_context.h"
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#include "content/public/browser/browser_task_traits.h"
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#include "content/public/browser/browser_thread.h"
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#include "content/public/browser/render_process_host.h"
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#include "mojo/public/cpp/bindings/associated_remote.h"
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namespace content {
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namespace {
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FieldTrialSynchronizer* g_instance = nullptr;
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// Notifies all renderer processes about the |group_name| that is finalized for
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// the given field trail (|field_trial_name|). This is called on UI thread.
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void NotifyAllRenderersOfFieldTrial(const std::string& field_trial_name,
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const std::string& group_name) {
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// To iterate over RenderProcessHosts, or to send messages to the hosts, we
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// need to be on the UI thread.
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DCHECK_CURRENTLY_ON(BrowserThread::UI);
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// Note this in the persistent profile as it will take a while for a new
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// "complete" profile to be generated.
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metrics::GlobalPersistentSystemProfile::GetInstance()->AddFieldTrial(
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field_trial_name, group_name);
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for (RenderProcessHost::iterator it(RenderProcessHost::AllHostsIterator());
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!it.IsAtEnd(); it.Advance()) {
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auto* host = it.GetCurrentValue();
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IPC::ChannelProxy* channel = host->GetChannel();
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// channel might be null in tests.
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if (host->IsInitializedAndNotDead() && channel) {
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mojo::AssociatedRemote<mojom::RendererVariationsConfiguration>
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renderer_variations_configuration;
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channel->GetRemoteAssociatedInterface(&renderer_variations_configuration);
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renderer_variations_configuration->SetFieldTrialGroup(field_trial_name,
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group_name);
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}
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}
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}
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} // namespace
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// static
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void FieldTrialSynchronizer::CreateInstance() {
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// Only 1 instance is allowed per process.
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DCHECK(!g_instance);
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g_instance = new FieldTrialSynchronizer();
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}
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FieldTrialSynchronizer::FieldTrialSynchronizer() {
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bool success = base::FieldTrialList::AddObserver(this);
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// Ensure the observer was actually registered.
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DCHECK(success);
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variations::VariationsIdsProvider::GetInstance()->AddObserver(this);
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NotifyAllRenderersOfVariationsHeader();
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}
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void FieldTrialSynchronizer::OnFieldTrialGroupFinalized(
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const std::string& field_trial_name,
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const std::string& group_name) {
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if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
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NotifyAllRenderersOfFieldTrial(field_trial_name, group_name);
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} else {
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GetUIThreadTaskRunner({})->PostTask(
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FROM_HERE, base::BindOnce(&NotifyAllRenderersOfFieldTrial,
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field_trial_name, group_name));
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}
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}
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// static
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void FieldTrialSynchronizer::NotifyAllRenderersOfVariationsHeader() {
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// To iterate over RenderProcessHosts, or to send messages to the hosts, we
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// need to be on the UI thread.
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DCHECK_CURRENTLY_ON(BrowserThread::UI);
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for (RenderProcessHost::iterator it(RenderProcessHost::AllHostsIterator());
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!it.IsAtEnd(); it.Advance()) {
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UpdateRendererVariationsHeader(it.GetCurrentValue());
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}
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}
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// static
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void FieldTrialSynchronizer::UpdateRendererVariationsHeader(
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RenderProcessHost* host) {
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if (!host->IsInitializedAndNotDead())
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return;
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IPC::ChannelProxy* channel = host->GetChannel();
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// |channel| might be null in tests.
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if (!channel)
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return;
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variations::VariationsClient* client =
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host->GetBrowserContext()->GetVariationsClient();
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// |client| might be null in tests.
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if (!client || client->IsOffTheRecord())
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return;
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mojo::AssociatedRemote<mojom::RendererVariationsConfiguration>
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renderer_variations_configuration;
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channel->GetRemoteAssociatedInterface(&renderer_variations_configuration);
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renderer_variations_configuration->SetVariationsHeaders(
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client->GetVariationsHeaders());
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}
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void FieldTrialSynchronizer::VariationIdsHeaderUpdated() {
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// PostTask to avoid recursive lock.
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GetUIThreadTaskRunner({})->PostTask(
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FROM_HERE,
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base::BindOnce(
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&FieldTrialSynchronizer::NotifyAllRenderersOfVariationsHeader));
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}
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FieldTrialSynchronizer::~FieldTrialSynchronizer() {
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NOTREACHED();
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}
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} // namespace content
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