Added Chrome-side support for EXT_blend_minmax WebGL extension

gpu/command_buffer/service/feature_info.cc

Index: gpu/command_buffer/service/feature_info.cc
diff --git a/gpu/command_buffer/service/feature_info.cc b/gpu/command_buffer/service/feature_info.cc
index 81df6b606052946fc9d8332cc6ef134ed03cdebf..9fa91b7ad8bf9386c7bf15343902e34154396013 100644
--- a/gpu/command_buffer/service/feature_info.cc
+++ b/gpu/command_buffer/service/feature_info.cc
@@ -777,6 +777,13 @@ void FeatureInfo::InitializeFeatures() {
     }
   }
 
+  if (extensions.Contains("GL_EXT_blend_minmax") ||
+      gfx::HasDesktopGLFeatures()) {
+    AddExtensionString("GL_EXT_blend_minmax");
+    validators_.equation.AddValue(GL_MIN_EXT);
+    validators_.equation.AddValue(GL_MAX_EXT);
+  }
+
   if (extensions.Contains("GL_EXT_frag_depth") || gfx::HasDesktopGLFeatures()) {
     AddExtensionString("GL_EXT_frag_depth");
     feature_flags_.ext_frag_depth = true;