During image destroy, delete textures only if we have a GL context.

gpu/command_buffer/service/context_group.cc

Index: gpu/command_buffer/service/context_group.cc
diff --git a/gpu/command_buffer/service/context_group.cc b/gpu/command_buffer/service/context_group.cc
index ba0437bfd4e389158b767c2c1398b41c33eb4d55..3ddb8da45501e734f5165445e7998da7baea3f53 100644
--- a/gpu/command_buffer/service/context_group.cc
+++ b/gpu/command_buffer/service/context_group.cc
@@ -324,6 +324,10 @@ void ContextGroup::Destroy(GLES2Decoder* decoder, bool have_context) {
     shader_manager_.reset();
   }
 
+  if (image_manager_ != NULL) {
+    image_manager_->Destroy(have_context);
+  }
+
   memory_tracker_ = NULL;
 }