Huge lag spikes are encountered from Canvas.SendWillRenderCanvases() when UnityEngine.UI.Image or UnityEngine.UI.Text are modified

This happens when:
"color" of UnityEngine.UI.Image is modified
"enabled" of UnityEngine.UI.Image is modified
"text" of UnityEngine.UI.Text is modified
It also seems to happen when "color" of UnityEngine.UI.Text is modified

Steps to reproduce:
1. Open attached project.
2. Open the profiler window and look at the "UI" and/or "CPU" and "Memory" tabs.
3. Open scene "LayoutRebuild_PleaseDontKThx.unity".
4. Press "Play".
5. Alt+Click on the "Expand" arrow next to "Canvas" gameobject.
6. Select the last gameobject in that hierarchy.
7. Click on the "Color" widget of the "Image" component of that gameobject to open the color selection window.
8. Change the color constantly by changing a slider or picking in the spectrum of the color selection window.
9. Observe the lag in the profiler window.

Expected result: Changed values should not cause that much CPU usage
Actual result: Constantly being changed values causes huge CPU usage

Reproduced in: 2017.1.0a4, 2017.1.0a1, 5.6.0f1, 5.6.0b9, 5.5.2f1, 5.5.1f1, , 5.4.4p4, 5.2.2p3