Add DNS prefetching

Turns out we did no have DNS prefetching. It requires an extra
component. The same component can also do pre-connect, but we do not
enable that, as it requires a predictive browsing backend.

[ChangeLog][Settings] DnsPrefetchEnabled added, but disabled by default.

Change-Id: Ieb036435b9f1a72a7be302e38e89e0c347c7176b
Reviewed-by: Jüri Valdmann <juri.valdmann@qt.io>

7 files changed, 41 insertions, 0 deletions

diff --git a/src/core/content_browser_client_qt.cpp b/src/core/content_browser_client_qt.cpp
index a7a2605eb..2d4ac3552 100644
--- a/src/core/content_browser_client_qt.cpp
+++ b/src/core/content_browser_client_qt.cpp
@@ -49,6 +49,7 @@
 #include "components/spellcheck/browser/spellcheck_message_filter_platform.h"
 #endif
 #endif
+#include "components/network_hints/browser/network_hints_message_filter.h"
 #include "content/browser/renderer_host/render_view_host_delegate.h"
 #include "content/common/url_schemes.h"
 #include "content/public/browser/browser_main_parts.h"
@@ -410,6 +411,11 @@ void ContentBrowserClientQt::RenderProcessWillLaunch(content::RenderProcessHost*
 {
     const int id = host->GetID();
     Profile *profile = Profile::FromBrowserContext(host->GetBrowserContext());
+    content::BrowserThread::PostTaskAndReplyWithResult(
+            content::BrowserThread::IO, FROM_HERE,
+            base::Bind(&net::URLRequestContextGetter::GetURLRequestContext, base::Unretained(profile->GetRequestContext())),
+            base::Bind(&ContentBrowserClientQt::AddNetworkHintsMessageFilter, base::Unretained(this), id));
+
     // FIXME: Add a settings variable to enable/disable the file scheme.
     content::ChildProcessSecurityPolicy::GetInstance()->GrantScheme(id, url::kFileScheme);
     static_cast<ProfileQt*>(host->GetBrowserContext())->m_profileAdapter->userResourceController()->renderProcessStartedWithHost(host);
@@ -776,6 +782,19 @@ void ContentBrowserClientQt::GetGeolocationRequestContext(
         base::BindOnce(&GetSystemRequestContextOnUIThread), std::move(callback));
 }
 
+void ContentBrowserClientQt::AddNetworkHintsMessageFilter(int render_process_id, net::URLRequestContext *context)
+{
+    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+    content::RenderProcessHost* host = content::RenderProcessHost::FromID(render_process_id);
+    if (!host)
+        return;
+
+    content::BrowserMessageFilter *network_hints_message_filter(
+                new network_hints::NetworkHintsMessageFilter(context->host_resolver()));
+    host->AddFilter(network_hints_message_filter);
+}
+
 bool ContentBrowserClientQt::AllowGetCookie(const GURL &url,
                                             const GURL &first_party,
                                             const net::CookieList & /*cookie_list*/,
diff --git a/src/core/content_browser_client_qt.h b/src/core/content_browser_client_qt.h
index 5a3fafd1a..a7f4313ea 100644
--- a/src/core/content_browser_client_qt.h
+++ b/src/core/content_browser_client_qt.h
@@ -198,6 +198,8 @@ public:
 
 private:
     void InitFrameInterfaces();
+    void AddNetworkHintsMessageFilter(int render_process_id, net::URLRequestContext *context);
+
     BrowserMainPartsQt* m_browserMainParts;
     std::unique_ptr<content::ResourceDispatcherHostDelegate> m_resourceDispatcherHostDelegate;
     scoped_refptr<ShareGroupQtQuick> m_shareGroupQtQuick;
diff --git a/src/core/qtwebengine.gni b/src/core/qtwebengine.gni
index 0fd8e4085..db3acfb50 100644
--- a/src/core/qtwebengine.gni
+++ b/src/core/qtwebengine.gni
@@ -16,6 +16,9 @@ deps = [
   "//components/cdm/renderer",
   "//components/error_page/common",
   "//components/keyed_service/content",
+  "//components/network_hints/browser",
+  "//components/network_hints/common",
+  "//components/network_hints/renderer",
   "//components/visitedlink/browser",
   "//components/visitedlink/renderer",
   "//components/web_cache/browser",
diff --git a/src/core/renderer/content_renderer_client_qt.cpp b/src/core/renderer/content_renderer_client_qt.cpp
index 707efc1c1..79c2294de 100644
--- a/src/core/renderer/content_renderer_client_qt.cpp
+++ b/src/core/renderer/content_renderer_client_qt.cpp
@@ -51,6 +51,7 @@
 #include "components/error_page/common/error.h"
 #include "components/error_page/common/error_page_params.h"
 #include "components/error_page/common/localized_error.h"
+#include "components/network_hints/renderer/prescient_networking_dispatcher.h"
 #if QT_CONFIG(webengine_printing_and_pdf)
 #include "components/printing/renderer/print_render_frame_helper.h"
 #endif
@@ -114,6 +115,8 @@ void ContentRendererClientQt::RenderThreadStarted()
     m_visitedLinkSlave.reset(new visitedlink::VisitedLinkSlave);
     m_webCacheImpl.reset(new web_cache::WebCacheImpl());
 
+    m_prescientNetworkingDispatcher.reset(new network_hints::PrescientNetworkingDispatcher());
+
     auto registry = std::make_unique<service_manager::BinderRegistry>();
     registry->AddInterface(m_visitedLinkSlave->GetBindCallback(),
                            base::ThreadTaskRunnerHandle::Get());
@@ -239,6 +242,11 @@ bool ContentRendererClientQt::IsLinkVisited(unsigned long long linkHash)
     return m_visitedLinkSlave->IsVisited(linkHash);
 }
 
+blink::WebPrescientNetworking *ContentRendererClientQt::GetPrescientNetworking()
+{
+    return m_prescientNetworkingDispatcher.get();
+}
+
 void ContentRendererClientQt::OnStart()
 {
     context()->connector()->BindConnectorRequest(std::move(m_connectorRequest));
diff --git a/src/core/renderer/content_renderer_client_qt.h b/src/core/renderer/content_renderer_client_qt.h
index a919c6ab6..2a353caa6 100644
--- a/src/core/renderer/content_renderer_client_qt.h
+++ b/src/core/renderer/content_renderer_client_qt.h
@@ -53,6 +53,10 @@ namespace error_page {
 class Error;
 }
 
+namespace network_hints {
+class PrescientNetworkingDispatcher;
+}
+
 namespace visitedlink {
 class VisitedLinkSlave;
 }
@@ -89,6 +93,7 @@ public:
 
     unsigned long long VisitedLinkHash(const char *canonicalUrl, size_t length) override;
     bool IsLinkVisited(unsigned long long linkHash) override;
+    blink::WebPrescientNetworking* GetPrescientNetworking() override;
     void AddSupportedKeySystems(std::vector<std::unique_ptr<media::KeySystemProperties>>* key_systems) override;
 
     void RunScriptsAtDocumentEnd(content::RenderFrame* render_frame) override;
@@ -123,6 +128,7 @@ private:
     service_manager::mojom::ConnectorRequest m_connectorRequest;
     std::unique_ptr<service_manager::ServiceContext> m_serviceContext;
     service_manager::BinderRegistry m_registry;
+    std::unique_ptr<network_hints::PrescientNetworkingDispatcher> m_prescientNetworkingDispatcher;
 
     DISALLOW_COPY_AND_ASSIGN(ContentRendererClientQt);
 };
diff --git a/src/core/web_engine_settings.cpp b/src/core/web_engine_settings.cpp
index 129a3f01d..2e48a806a 100644
--- a/src/core/web_engine_settings.cpp
+++ b/src/core/web_engine_settings.cpp
@@ -298,6 +298,7 @@ void WebEngineSettings::initDefaults()
         s_defaultAttributes.insert(PlaybackRequiresUserGesture, playbackRequiresUserGesture);
         s_defaultAttributes.insert(WebRTCPublicInterfacesOnly, false);
         s_defaultAttributes.insert(JavascriptCanPaste, false);
+        s_defaultAttributes.insert(DnsPrefetchEnabled, false);
     }
 
     if (s_defaultFontFamilies.isEmpty()) {
@@ -390,6 +391,7 @@ void WebEngineSettings::applySettingsToWebPreferences(content::WebPreferences *p
                                : content::AutoplayPolicy::kNoUserGestureRequired;
     }
     prefs->dom_paste_enabled = testAttribute(JavascriptCanPaste);
+    prefs->dns_prefetching_enabled = testAttribute(DnsPrefetchEnabled);
 
     // Fonts settings.
     prefs->standard_font_family_map[content::kCommonScript] = toString16(fontFamily(StandardFont));
diff --git a/src/core/web_engine_settings.h b/src/core/web_engine_settings.h
index ec99c5a29..06a7a6004 100644
--- a/src/core/web_engine_settings.h
+++ b/src/core/web_engine_settings.h
@@ -102,6 +102,7 @@ public:
         PlaybackRequiresUserGesture,
         WebRTCPublicInterfacesOnly,
         JavascriptCanPaste,
+        DnsPrefetchEnabled,
     };
 
     // Must match the values from the public API in qwebenginesettings.h.