Fix ScopedGLContextChecker with QTWEBENGINE_DISABLE_GPU_THREAD=1

The ScopedGLContextChecker, which deactivates the current
QOpenGLContext when executing Chromium tasks, is currently enabled
only if QOpenGLContext::supportsThreadedOpenGL() is false. But the gpu
thread can nowadays be disabled also with an environment variable and
ScopedGLContextChecker needs to take this into account.

Change-Id: I012524538b49b033ed053dbc41ed4350db916542
Reviewed-by: Michal Klocek <michal.klocek@qt.io>
(cherry picked from commit 5988cec1a1b59aa163042a419c4c2e978bb814bb)

4 files changed, 18 insertions, 15 deletions

diff --git a/src/core/browser_main_parts_qt.cpp b/src/core/browser_main_parts_qt.cpp
index 925c18664..45056fec2 100644
--- a/src/core/browser_main_parts_qt.cpp
+++ b/src/core/browser_main_parts_qt.cpp
@@ -190,7 +190,7 @@ private:
         }
 
     private:
-        bool m_enabled = !QOpenGLContext::supportsThreadedOpenGL();
+        bool m_enabled = WebEngineContext::isGpuServiceOnUIThread();
 #endif // QT_CONFIG(opengl)
     };
 
diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index 7cc84eae7..11692c2d1 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -496,6 +496,17 @@ const static char kChromiumFlagsEnv[] = "QTWEBENGINE_CHROMIUM_FLAGS";
 const static char kDisableSandboxEnv[] = "QTWEBENGINE_DISABLE_SANDBOX";
 const static char kDisableInProcGpuThread[] = "QTWEBENGINE_DISABLE_GPU_THREAD";
 
+// static
+bool WebEngineContext::isGpuServiceOnUIThread()
+{
+    static bool threadedGpu =
+#if QT_CONFIG(opengl) && !defined(Q_OS_MACOS)
+            QOpenGLContext::supportsThreadedOpenGL() &&
+#endif
+            !qEnvironmentVariableIsSet(kDisableInProcGpuThread);
+    return !threadedGpu;
+}
+
 static void appendToFeatureList(std::string &featureList, const char *feature)
 {
     if (featureList.empty())
@@ -606,16 +617,6 @@ WebEngineContext::WebEngineContext()
     if (isDesktopGLOrSoftware || isGLES2Context)
         parsedCommandLine->AppendSwitch(switches::kDisableES3GLContext);
 #endif
-    bool threadedGpu = false;
-#if QT_CONFIG(opengl)
-    threadedGpu = QOpenGLContext::supportsThreadedOpenGL();
-#if defined(Q_OS_MACOS)
-    // QtBase disabled it when building on 10.14+, unfortunately we still need it
-    // until we have fixed single-threaded viz-display-compositor.
-    threadedGpu = true;
-#endif
-#endif
-    threadedGpu = threadedGpu && !qEnvironmentVariableIsSet(kDisableInProcGpuThread);
 
     bool enableViz = !parsedCommandLine->HasSwitch("disable-viz-display-compositor");
     parsedCommandLine->RemoveSwitch("disable-viz-display-compositor");
@@ -774,7 +775,7 @@ WebEngineContext::WebEngineContext()
         parsedCommandLine->AppendSwitch(switches::kDisableGpu);
     }
 
-    registerMainThreadFactories(threadedGpu);
+    registerMainThreadFactories();
 
     SetContentClient(new ContentClientQt);
 
diff --git a/src/core/web_engine_context.h b/src/core/web_engine_context.h
index 6cbd5c8e5..e2190f8a2 100644
--- a/src/core/web_engine_context.h
+++ b/src/core/web_engine_context.h
@@ -123,13 +123,15 @@ public:
 
     static gpu::SyncPointManager *syncPointManager();
 
+    static bool isGpuServiceOnUIThread();
+
 private:
     friend class base::RefCounted<WebEngineContext>;
     friend class ProfileAdapter;
     WebEngineContext();
     ~WebEngineContext();
 
-    static void registerMainThreadFactories(bool threaded);
+    static void registerMainThreadFactories();
     static void destroyGpuProcess();
 
     std::unique_ptr<base::RunLoop> m_runLoop;
diff --git a/src/core/web_engine_context_threads.cpp b/src/core/web_engine_context_threads.cpp
index ba3e18499..5f9e345f7 100644
--- a/src/core/web_engine_context_threads.cpp
+++ b/src/core/web_engine_context_threads.cpp
@@ -125,11 +125,11 @@ void WebEngineContext::destroyGpuProcess()
 }
 
 // static
-void WebEngineContext::registerMainThreadFactories(bool threaded)
+void WebEngineContext::registerMainThreadFactories()
 {
     content::UtilityProcessHost::RegisterUtilityMainThreadFactory(content::CreateInProcessUtilityThread);
     content::RenderProcessHostImpl::RegisterRendererMainThreadFactory(content::CreateInProcessRendererThread);
-    if (threaded)
+    if (!isGpuServiceOnUIThread())
         content::RegisterGpuMainThreadFactory(content::CreateInProcessGpuThread);
     else
         content::RegisterGpuMainThreadFactory(createGpuThreadController);