Teach GPU command buffer whether a context is webgl.

gpu/command_buffer/tests/gl_manager.h

Index: gpu/command_buffer/tests/gl_manager.h
diff --git a/gpu/command_buffer/tests/gl_manager.h b/gpu/command_buffer/tests/gl_manager.h
index c163ac01cc9f94a5bd835610014861c2e05ce516..f86cc0d39dcac6e663d046a93a2383e96a2ff1b5 100644
--- a/gpu/command_buffer/tests/gl_manager.h
+++ b/gpu/command_buffer/tests/gl_manager.h
@@ -61,6 +61,10 @@ class GLManager : private GpuControl {
     bool lose_context_when_out_of_memory;
     // Whether or not it's ok to lose the context.
     bool context_lost_allowed;
+    // 0 indicates not WebGL context - default.
+    // 1 indicates WebGL 1 context.
+    // 2 indicates WebGL 2 context.
+    unsigned webgl_version;
   };
   GLManager();
   ~GLManager() override;