Revert "Move assistant icon animation to CompositorAnimationOberver"

This reverts commit 33fc6c64a3b5af5627b7e28874f4583793e74da8.

Reason for revert: One or the other of this CL and https://crrev.com/c/748268 (perhaps both in combination?) broke PaletteTrayTestWithVoiceInteraction.StylusBarrelButtonActivatesHighlighter on Linux ChromiumOS Tests (dbg)(1):

https://uberchromegw.corp.google.com/i/chromium.chromiumos/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%281%29/builds/31692

The connection to these voice interaction Cls seems pretty clear. I can't identify which one it is, though, so while I apologize for the trouble, I'm going to revert both to ensure that the bot turns green again.

Original change's description:
> Move assistant icon animation to CompositorAnimationOberver
> 
> BUG=None
> TEST=locally build and see animation running as before.
> 
> Change-Id: I1eb62490108beaaec0795adb4251054c03b364e1
> Reviewed-on: https://chromium-review.googlesource.com/748273
> Commit-Queue: Xiaohui Chen <xiaohuic@chromium.org>
> Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#513211}

TBR=xiyuan@chromium.org,xiaohuic@chromium.org

Change-Id: I5ef677c189808601f8e357f56a171bf920b10fa0
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: None
Reviewed-on: https://chromium-review.googlesource.com/749851
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513272}
  void AddPaintLayer(PaintedShape painted_shape) {
    ui::LayerDelegate* delegate = nullptr;
    switch (painted_shape) {
      case TOP_LEFT_CIRCLE:
      case TOP_RIGHT_CIRCLE:
      case BOTTOM_RIGHT_CIRCLE:
      case BOTTOM_LEFT_CIRCLE:
        delegate = circle_layer_delegate_.get();
        break;
      case HORIZONTAL_RECT:
      case VERTICAL_RECT:
        delegate = rect_layer_delegate_.get();
        break;
      case PAINTED_SHAPE_COUNT:
        NOTREACHED() << "PAINTED_SHAPE_COUNT is not an actual shape type.";
        break;
    }

    ui::Layer* layer = new ui::Layer();
    Add(layer);

    layer->SetBounds(gfx::Rect(small_size_));
    layer->SetFillsBoundsOpaquely(false);
    layer->set_delegate(delegate);
    layer->SetVisible(true);
    layer->SetOpacity(1.0);
    layer->SetMasksToBounds(false);
    layer->set_name("PAINTED_SHAPE_COUNT:" + ToLayerName(painted_shape));

    painted_layers_[static_cast<int>(painted_shape)].reset(layer);
  }

  void AddPaintLayer(PaintedShape painted_shape) {
    ui::LayerDelegate* delegate = nullptr;
    switch (painted_shape) {
      case TOP_LEFT_CIRCLE:
      case TOP_RIGHT_CIRCLE:
      case BOTTOM_RIGHT_CIRCLE:
      case BOTTOM_LEFT_CIRCLE:
        delegate = circle_layer_delegate_.get();
        break;
      case HORIZONTAL_RECT:
      case VERTICAL_RECT:
        delegate = rect_layer_delegate_.get();
        break;
      case PAINTED_SHAPE_COUNT:
        NOTREACHED() << "PAINTED_SHAPE_COUNT is not an actual shape type.";
        break;
    }

    ui::Layer* layer = new ui::Layer();
    Add(layer);

    layer->SetBounds(gfx::Rect(small_size_));
    layer->SetFillsBoundsOpaquely(false);
    layer->set_delegate(delegate);
    layer->SetVisible(true);
    layer->SetOpacity(1.0);
    layer->SetMasksToBounds(false);
    layer->set_name("PAINTED_SHAPE_COUNT:" + ToLayerName(painted_shape));

    painted_layers_[static_cast<int>(painted_shape)].reset(layer);
  }
