Disable WebEngineContext dump by default

Keep it enabled for simplebrowser and quicknanobrowser examples. Also
add documentation how to enable it.

[ChangeLog][WebEngineCore] Disabled WebEngineContext dump by default.

Fixes: QTBUG-109040
Pick-to: 6.5
Change-Id: I4bd3c0e9eb532771f9b455863324e9dacaae884a
Reviewed-by: Michal Klocek <michal.klocek@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

4 files changed, 33 insertions, 19 deletions

diff --git a/examples/webenginequick/quicknanobrowser/main.cpp b/examples/webenginequick/quicknanobrowser/main.cpp
index 519cfd089..850b8c443 100644
--- a/examples/webenginequick/quicknanobrowser/main.cpp
+++ b/examples/webenginequick/quicknanobrowser/main.cpp
@@ -12,6 +12,7 @@
 
 #include <QtCore/QCommandLineParser>
 #include <QtCore/QCommandLineOption>
+#include <QtCore/QLoggingCategory>
 
 static QUrl startupUrl(const QCommandLineParser &parser)
 {
@@ -31,6 +32,7 @@ int main(int argc, char **argv)
     QtWebEngineQuick::initialize();
 
     QGuiApplication app(argc, argv);
+    QLoggingCategory::setFilterRules(QStringLiteral("qt.webenginecontext.debug=true"));
 
     QCommandLineParser parser;
     parser.addHelpOption();
diff --git a/examples/webenginewidgets/simplebrowser/main.cpp b/examples/webenginewidgets/simplebrowser/main.cpp
index 477a8171b..b945ef27e 100644
--- a/examples/webenginewidgets/simplebrowser/main.cpp
+++ b/examples/webenginewidgets/simplebrowser/main.cpp
@@ -5,6 +5,7 @@
 #include "browserwindow.h"
 #include "tabwidget.h"
 #include <QApplication>
+#include <QLoggingCategory>
 #include <QWebEngineProfile>
 #include <QWebEngineSettings>
 
@@ -24,6 +25,7 @@ int main(int argc, char **argv)
 
     QApplication app(argc, argv);
     app.setWindowIcon(QIcon(QStringLiteral(":AppLogoColor.png")));
+    QLoggingCategory::setFilterRules(QStringLiteral("qt.webenginecontext.debug=true"));
 
     QWebEngineProfile::defaultProfile()->settings()->setAttribute(QWebEngineSettings::PluginsEnabled, true);
     QWebEngineProfile::defaultProfile()->settings()->setAttribute(QWebEngineSettings::DnsPrefetchEnabled, true);
diff --git a/src/core/doc/src/qtwebengine-debugging.qdoc b/src/core/doc/src/qtwebengine-debugging.qdoc
index 3599ec55e..3bb6a7029 100644
--- a/src/core/doc/src/qtwebengine-debugging.qdoc
+++ b/src/core/doc/src/qtwebengine-debugging.qdoc
@@ -92,6 +92,15 @@
     QTWEBENGINE_CHROMIUM_FLAGS="--disable-logging" mybrowser
     \endcode
 
-    QTWEBENGINE_CHROMIUM_FLAGS can also be set using {qputenv} from within the
+    QTWEBENGINE_CHROMIUM_FLAGS can also be set using \c qputenv from within the
     application if called before QtWebEngineQuick::initialize().
+
+    \section1 Dump WebEngineContext Information
+
+    For dumping the WebEngineContext information, you can set the \c QT_LOGGING_RULES
+    environment variable to \c "qt.webenginecontext.debug=true".
+
+    The output contains information about the graphical backend, and the way how \QWE
+    is initialized for the application. This is particularly useful for reproducing
+    issues.
 */
diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index 71855c8c2..ee90a5810 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -119,6 +119,8 @@ QT_END_NAMESPACE
 
 namespace QtWebEngineCore {
 
+Q_LOGGING_CATEGORY(webEngineContextLog, "qt.webenginecontext")
+
 #if QT_CONFIG(opengl)
 
 static bool usingSupportedSGBackend()
@@ -235,8 +237,7 @@ void dummyGetPluginCallback(const std::vector<content::WebPluginInfo>&)
 
 static void logContext(const char *glType, base::CommandLine *cmd)
 {
-    QLoggingCategory webEngineContextLog("qt.webenginecontext");
-    if (webEngineContextLog.isInfoEnabled()) {
+    if (Q_UNLIKELY(webEngineContextLog().isDebugEnabled())) {
 #if QT_CONFIG(opengl)
         const QSurfaceFormat sharedFormat = qt_gl_global_share_context()->format();
         const auto profile = QMetaEnum::fromType<QSurfaceFormat::OpenGLContextProfile>().valueToKey(
@@ -248,23 +249,23 @@ static void logContext(const char *glType, base::CommandLine *cmd)
         for (const auto &pair : switch_map)
             params << " * " << toQt(pair.first)
                    << toQt(pair.second) << "\n";
-        qCInfo(webEngineContextLog,
-               "\n\nGL Type: %s\n"
-               "Surface Type: %s\n"
-               "Surface Profile: %s\n"
-               "Surface Version: %d.%d\n"
-               "QSG RHI Backend: %s\n"
-               "Using Supported QSG Backend: %s\n"
-               "Using Software Dynamic GL: %s\n"
-               "Using Multithreaded OpenGL: %s\n\n"
-               "Init Parameters:\n %s",
-               glType, type, profile, sharedFormat.majorVersion(), sharedFormat.minorVersion(),
-               qUtf8Printable(QSGRhiSupport::instance()->rhiBackendName()),
-               usingSupportedSGBackend() ? "yes" : "no", usingSoftwareDynamicGL() ? "yes" : "no",
-               !WebEngineContext::isGpuServiceOnUIThread() ? "yes" : "no",
-               qPrintable(params.join(" ")));
+        qCDebug(webEngineContextLog,
+                "\n\nGL Type: %s\n"
+                "Surface Type: %s\n"
+                "Surface Profile: %s\n"
+                "Surface Version: %d.%d\n"
+                "QSG RHI Backend: %s\n"
+                "Using Supported QSG Backend: %s\n"
+                "Using Software Dynamic GL: %s\n"
+                "Using Multithreaded OpenGL: %s\n\n"
+                "Init Parameters:\n %s",
+                glType, type, profile, sharedFormat.majorVersion(), sharedFormat.minorVersion(),
+                qUtf8Printable(QSGRhiSupport::instance()->rhiBackendName()),
+                usingSupportedSGBackend() ? "yes" : "no", usingSoftwareDynamicGL() ? "yes" : "no",
+                !WebEngineContext::isGpuServiceOnUIThread() ? "yes" : "no",
+                qPrintable(params.join(" ")));
 #else
-        qCInfo(webEngineContextLog) << "WebEngine compiled with no opengl enabled.";
+        qCDebug(webEngineContextLog) << "WebEngine compiled with no opengl enabled.";
 #endif //QT_CONFIG(opengl)
     }
 }