X11: Use better visuals for OpenGL

gpu/ipc/service/gpu_command_buffer_stub.cc

Index: gpu/ipc/service/gpu_command_buffer_stub.cc
diff --git a/gpu/ipc/service/gpu_command_buffer_stub.cc b/gpu/ipc/service/gpu_command_buffer_stub.cc
index 412d9a97182600dd249a90304302123b615ba887..b61e90231121d0cbd6d8dd18e36ef33982d41e9f 100644
--- a/gpu/ipc/service/gpu_command_buffer_stub.cc
+++ b/gpu/ipc/service/gpu_command_buffer_stub.cc
@@ -535,9 +535,9 @@ bool GpuCommandBufferStub::Initialize(
   scoped_refptr<gl::GLContext> context;
   gl::GLShareGroup* gl_share_group = channel_->share_group();
   if (use_virtualized_gl_context_ && gl_share_group) {
-    context = gl_share_group->GetSharedContext();
+    context = gl_share_group->GetSharedContext(surface_.get());
     if (!context.get()) {
-      context = gl::init::CreateGLContext(gl_share_group, default_surface,
+      context = gl::init::CreateGLContext(gl_share_group, surface_.get(),
                                           init_params.attribs.gpu_preference);
       if (!context.get()) {
         DLOG(ERROR) << "Failed to create shared context for virtualization.";
@@ -546,7 +546,7 @@ bool GpuCommandBufferStub::Initialize(
       // Ensure that context creation did not lose track of the intended
       // gl_share_group.
       DCHECK(context->share_group() == gl_share_group);
-      gl_share_group->SetSharedContext(context.get());
+      gl_share_group->SetSharedContext(surface_.get(), context.get());

[Julien Isorce Samsung, 2016/09/28 17:42:51]

Just for my understanding, could you explain these changes, I mean not exactly
this line but the overall idea about it and above ? Thx

[Tom (Use chromium acct), 2016/09/28 18:36:01]

Before we were always using the default visual in the GPU process.  Now, we may
be using the default visual and a transparent visual at the same time across
different surfaces, however these are incompatible with each other and cannot be
made current with each other.  So when we get a shared context, we need to pass
a compatible surface now so we know which one to use.

     }
     // This should be either:
     // (1) a non-virtual GL context, or