Implement PluginServiceFilterQt

Let Chromium know about the status of plugin availability from
WebEngineSettings. This way it can decide whether the response is
a download and it has more benefits:
- It doesn't have to start a new load request to download a PDF file,
it just treats the original response accordingly.
- Fixes websites which are protected from cross-domain requests (e.g. by
checking the Referer header) and/or redirecting requests for PDFs.
Calling DownloadManager "manually" and not passing the original request
headers did not work when the server relied on them.

Task-number: QTBUG-78114
Change-Id: I8cfa90c211418001c60c4b2f0f8818ee453101fc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

5 files changed, 180 insertions, 6 deletions

diff --git a/src/core/browser_main_parts_qt.cpp b/src/core/browser_main_parts_qt.cpp
index 1add722a5..bc0499bca 100644
--- a/src/core/browser_main_parts_qt.cpp
+++ b/src/core/browser_main_parts_qt.cpp
@@ -59,10 +59,12 @@
 #include "content/public/common/service_manager_connection.h"
 #include "extensions/buildflags/buildflags.h"
 #if BUILDFLAG(ENABLE_EXTENSIONS)
+#include "content/public/browser/plugin_service.h"
 #include "extensions/common/constants.h"
 #include "extensions/common/extensions_client.h"
 #include "extensions/extensions_browser_client_qt.h"
 #include "extensions/extension_system_factory_qt.h"
+#include "extensions/plugin_service_filter_qt.h"
 #include "common/extensions/extensions_client_qt.h"
 #endif //BUILDFLAG(ENABLE_EXTENSIONS)
 #include "services/service_manager/public/cpp/connector.h"
@@ -250,6 +252,9 @@ void BrowserMainPartsQt::PreMainMessageLoopRun()
     extensions::ExtensionsClient::Set(new extensions::ExtensionsClientQt());
     extensions::ExtensionsBrowserClient::Set(new extensions::ExtensionsBrowserClientQt());
     extensions::ExtensionSystemFactoryQt::GetInstance();
+
+    content::PluginService *plugin_service = content::PluginService::GetInstance();
+    plugin_service->SetFilter(extensions::PluginServiceFilterQt::GetInstance());
 #endif //ENABLE_EXTENSIONS
 }
 
diff --git a/src/core/core_chromium.pri b/src/core/core_chromium.pri
index 2653c1e57..108dd3221 100644
--- a/src/core/core_chromium.pri
+++ b/src/core/core_chromium.pri
@@ -326,6 +326,7 @@ qtConfig(webengine-extensions) {
         extensions/extensions_browser_client_qt.cpp \
         extensions/messaging_delegate_qt.cpp \
         extensions/mime_handler_view_guest_delegate_qt.cpp \
+        extensions/plugin_service_filter_qt.cpp \
         net/plugin_response_interceptor_url_loader_throttle.cpp \
         renderer/extensions/extensions_dispatcher_delegate_qt.cpp \
         renderer/extensions/extensions_renderer_client_qt.cpp \
@@ -344,6 +345,7 @@ qtConfig(webengine-extensions) {
         extensions/extensions_browser_client_qt.h \
         extensions/messaging_delegate_qt.h \
         extensions/mime_handler_view_guest_delegate_qt.h \
+        extensions/plugin_service_filter_qt.h \
         net/plugin_response_interceptor_url_loader_throttle.h \
         renderer/extensions/extensions_dispatcher_delegate_qt.h \
         renderer/extensions/extensions_renderer_client_qt.h \
diff --git a/src/core/extensions/plugin_service_filter_qt.cpp b/src/core/extensions/plugin_service_filter_qt.cpp
new file mode 100644
index 000000000..b29dbbeab
--- /dev/null
+++ b/src/core/extensions/plugin_service_filter_qt.cpp
@@ -0,0 +1,99 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "extensions/plugin_service_filter_qt.h"
+
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
+
+#include "web_contents_delegate_qt.h"
+
+using namespace QtWebEngineCore;
+
+namespace extensions {
+
+// static
+PluginServiceFilterQt *PluginServiceFilterQt::GetInstance() {
+    return base::Singleton<PluginServiceFilterQt>::get();
+}
+
+bool PluginServiceFilterQt::IsPluginAvailable(int render_process_id,
+                                              int render_frame_id,
+                                              const GURL &url,
+                                              const url::Origin &main_frame_origin,
+                                              content::WebPluginInfo *plugin)
+{
+    content::RenderFrameHost *frame_host = content::RenderFrameHost::FromID(render_process_id, render_frame_id);
+    content::WebContents *web_contents = content::WebContents::FromRenderFrameHost(frame_host);
+    if (!web_contents) {
+        // Availability checked somewhere before/during WebContents initialization. Let it load and enable
+        // all the plugins at this phase. This information will be queried again when receiving the response
+        // for the requested content. Postponing our decision and enabling/blocking there makes WebEngineSettings
+        // modifiable in runtime without reconstructing WebContents.
+        return true;
+    }
+
+    if (web_contents->IsInnerWebContentsForGuest())
+        web_contents = web_contents->GetOuterWebContents();
+
+    if (auto *delegate = static_cast<WebContentsDelegateQt *>(web_contents->GetDelegate())) {
+        const WebEngineSettings *settings = delegate->webEngineSettings();
+        if (!settings->testAttribute(WebEngineSettings::PdfViewerEnabled)
+            || !settings->testAttribute(WebEngineSettings::PluginsEnabled))
+            return false;
+    }
+
+    return true;
+}
+
+bool PluginServiceFilterQt::CanLoadPlugin(int render_process_id,
+                                          const base::FilePath &path)
+{
+    return true;
+}
+
+PluginServiceFilterQt::PluginServiceFilterQt()
+{
+}
+
+PluginServiceFilterQt::~PluginServiceFilterQt()
+{
+}
+
+} // namespace extensions
diff --git a/src/core/extensions/plugin_service_filter_qt.h b/src/core/extensions/plugin_service_filter_qt.h
new file mode 100644
index 000000000..ea5f082f2
--- /dev/null
+++ b/src/core/extensions/plugin_service_filter_qt.h
@@ -0,0 +1,71 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtWebEngine module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef PLUGIN_SERVICE_FILTER_QT
+#define PLUGIN_SERVICE_FILTER_QT
+
+#include "content/public/browser/plugin_service_filter.h"
+
+#include "base/memory/singleton.h"
+
+namespace extensions {
+
+class PluginServiceFilterQt : public content::PluginServiceFilter {
+public:
+    static PluginServiceFilterQt* GetInstance();
+
+    bool IsPluginAvailable(int render_process_id,
+                           int render_frame_id,
+                           const GURL &url,
+                           const url::Origin &main_frame_origin,
+                           content::WebPluginInfo *plugin) override;
+
+    bool CanLoadPlugin(int render_process_id,
+                       const base::FilePath &path) override;
+
+private:
+    friend struct base::DefaultSingletonTraits<PluginServiceFilterQt>;
+
+    PluginServiceFilterQt();
+    ~PluginServiceFilterQt();
+};
+
+} // namespace extensions
+
+#endif // PLUGIN_SERVICE_FILTER_QT
diff --git a/src/core/net/plugin_response_interceptor_url_loader_throttle.cpp b/src/core/net/plugin_response_interceptor_url_loader_throttle.cpp
index 326bdabb1..d868e4f54 100644
--- a/src/core/net/plugin_response_interceptor_url_loader_throttle.cpp
+++ b/src/core/net/plugin_response_interceptor_url_loader_throttle.cpp
@@ -91,12 +91,9 @@ void PluginResponseInterceptorURLLoaderThrottle::WillProcessResponse(const GURL
     WebEngineSettings *settings = contentsDelegate->webEngineSettings();
     if (!settings->testAttribute(WebEngineSettings::PdfViewerEnabled)
         || !settings->testAttribute(WebEngineSettings::PluginsEnabled)) {
-        // If the applications has been set up to always download PDF files to open them in an
-        // external viewer, trigger the download.
-        std::unique_ptr<download::DownloadUrlParameters> params(
-                content::DownloadRequestUtils::CreateDownloadForWebContentsMainFrame(web_contents, response_url,
-                                                                                     MISSING_TRAFFIC_ANNOTATION));
-        content::BrowserContext::GetDownloadManager(web_contents->GetBrowserContext())->DownloadUrl(std::move(params));
+        // PluginServiceFilterQt will inform the URLLoader about the disabled state of plugins
+        // and we can expect the download to be triggered automatically. It's unnecessary to
+        // go further and start the guest view embedding process.
         return;
     }