FIXUP: "Shut GL down on process exit to silence Direct3D11 warnings"

Speculative fix for CI failures on Ubuntu. The GL shutdown only
matters on Windows (so far), so it's now placed inside #if guards.

Change-Id: Iec8c8e5495026162421f209aa1fcd092ff7b9634
Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/583052
Reviewed-by: Peter Varga <[email protected]>
(cherry picked from commit 9eb5f1c)
Reviewed-on: https://codereview.qt-project.org/c/qt/qtwebengine-chromium/+/583077
Reviewed-by: Qt Cherry-pick Bot <[email protected]>

Author: Kaloyan Chehlarski

chromium/gpu/ipc/service/gpu_init.cc

@@ -296,13 +296,15 @@ void SetupGLDisplayManagerEGL(const GPUInfo& gpu_info,
 GpuInit::GpuInit() = default;
 
 GpuInit::~GpuInit() {
+#if BUILDFLAG(IS_WIN)
   if (gl::GetGLImplementation() != gl::kGLImplementationDisabled) {
     auto *gl_display = gl::init::GetOrInitializeGLOneOffPlatformImplementation(
         false, false, false, gl::GpuPreference::kDefault);
     if (gl_display) {
       gl::init::ShutdownGL(gl_display, false);
     }
   }
+#endif // BUILDFLAG(IS_WIN)
 
   StopForceDiscreteGPU();
 }