Remove WebGL2 constraint that requires draw*Instanced() calls to fail when no vertex attrib has zer…

gpu/command_buffer/service/vertex_attrib_manager.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "gpu/command_buffer/service/vertex_attrib_manager.h"
 
 #include <stdint.h>
 
 #include <list>
 
@@ skipping 254 matching lines @@
         if (buffer->IsClientSideArray()) {
           // Don't disable attrib 0 since it's special.
           if (attrib->index() > 0) {
             glDisableVertexAttribArray(attrib->index());
           }
         }
       }
     }
   }
 
-  // Instanced drawing needs at least one enabled attribute with divisor zero.
+  // Due to D3D9 limitation, in ES2/WebGL1, instanced drawing needs at least
+  // one enabled attribute with divisor zero. This does not apply to D3D11,
+  // therefore, it also does not apply to ES3/WebGL2.
   // Non-instanced drawing is fine with having no attributes at all, but if
   // there are attributes, at least one should have divisor zero.
   // (See ANGLE_instanced_arrays spec)
-  if (!divisor0 && (instanced || have_enabled_active_attribs)) {
+  if (feature_info->IsWebGL1OrES2Context() && !divisor0 &&
+      (instanced || have_enabled_active_attribs)) {
     ERRORSTATE_SET_GL_ERROR(
         error_state, GL_INVALID_OPERATION, function_name,
         "attempt to draw with all attributes having non-zero divisors");
     return false;
   }
 
   if (current_buffer_id != kInitialBufferId) {
     // Restore the buffer binding.
     decoder->RestoreBufferBindings();
   }
 
   return true;
 }
 
 }  // namespace gles2
 }  // namespace gpu