command_buffer: Add support for creating non-WebGL ES 3 contexts

gpu/command_buffer/common/gles2_cmd_utils.h

Index: gpu/command_buffer/common/gles2_cmd_utils.h
diff --git a/gpu/command_buffer/common/gles2_cmd_utils.h b/gpu/command_buffer/common/gles2_cmd_utils.h
index c514d3a4c5bd6f22a9fadb0c17990f4edfd124bf..9877884ad10076f4e6e6a63f7f693fece896ac10 100644
--- a/gpu/command_buffer/common/gles2_cmd_utils.h
+++ b/gpu/command_buffer/common/gles2_cmd_utils.h
@@ -213,6 +213,12 @@ class GLES2_UTILS_EXPORT GLES2Util {
 
 struct GLES2_UTILS_EXPORT ContextCreationAttribHelper {
   ContextCreationAttribHelper();
+  enum ContextType {

[Zhenyao Mo, 2015/08/28 17:16:25]

Can we move this outside ContextCreationAttribHelper, so we can reference it as
gpu::gles2::ContextType, and use it everywhere instead of multiple enum
definition?

[Kimmo Kinnunen, 2015/08/31 12:23:13]

Done.

+    CONTEXT_TYPE_WEBGL1,
+    CONTEXT_TYPE_WEBGL2,
+    CONTEXT_TYPE_OPENGLES2,
+    CONTEXT_TYPE_OPENGLES3
+  };
 
   void Serialize(std::vector<int32_t>* attribs) const;
   bool Parse(const std::vector<int32_t>& attribs);
@@ -230,8 +236,7 @@ struct GLES2_UTILS_EXPORT ContextCreationAttribHelper {
   bool bind_generates_resource;
   bool fail_if_major_perf_caveat;
   bool lose_context_when_out_of_memory;
-  // 0 if not a WebGL context.
-  unsigned webgl_version;
+  ContextType context_type;
 };
 
 }  // namespace gles2