Teach GPU command buffer whether a context is webgl.

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.h b/gpu/command_buffer/service/gles2_cmd_decoder.h
index 26f695cf8ee42bf4f708cdc52e21b238e2e04273..81ff74af41d60c8b8ca8091723297046052e4f65 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.h
@@ -45,10 +45,12 @@ struct ContextState;
 
 struct DisallowedFeatures {
   DisallowedFeatures()
-      : gpu_memory_manager(false) {
+      : gpu_memory_manager(false),
+        npot_support(false) {
   }
 
   bool gpu_memory_manager;
+  bool npot_support;
 };
 
 typedef base::Callback<void(const std::string& key,