Fix fbo completeness check when non-base-level texture image is attached.

gpu/command_buffer/service/framebuffer_manager.cc

Index: gpu/command_buffer/service/framebuffer_manager.cc
diff --git a/gpu/command_buffer/service/framebuffer_manager.cc b/gpu/command_buffer/service/framebuffer_manager.cc
index 55ed2e1a1f8e1bec6ef38e86b8c8bea46d9b11df..637c6b70e53c8cc794bbc867e9566fc4c9c4cad2 100644
--- a/gpu/command_buffer/service/framebuffer_manager.cc
+++ b/gpu/command_buffer/service/framebuffer_manager.cc
@@ -243,6 +243,9 @@ class TextureAttachment
   }
 
   bool IsLayerValid() const override {
+    if (!Is3D()) {
+      return true;
+    }
     Texture* texture = texture_ref_->texture();
     DCHECK(texture);
     GLsizei width, height, depth;