Refactor GL bindings so there is no global GLApi or DriverGL.

gpu/command_buffer/service/gl_context_virtual.h

Index: gpu/command_buffer/service/gl_context_virtual.h
diff --git a/gpu/command_buffer/service/gl_context_virtual.h b/gpu/command_buffer/service/gl_context_virtual.h
index c7187799316cfac828469874fbf2c21a7b277047..d8c7c911fe95f8b126acc80b7475148a9f7ab347 100644
--- a/gpu/command_buffer/service/gl_context_virtual.h
+++ b/gpu/command_buffer/service/gl_context_virtual.h
@@ -40,6 +40,8 @@ class GPU_EXPORT GLContextVirtual : public gl::GLContext {
   void* GetHandle() override;
   scoped_refptr<gl::GPUTimingClient> CreateGPUTimingClient() override;
   void OnSetSwapInterval(int interval) override;
+  std::string GetGLVersion() override;
+  std::string GetGLRenderer() override;
   std::string GetExtensions() override;
   void SetSafeToForceGpuSwitch() override;
   bool WasAllocatedUsingRobustnessExtension() override;