Detect non-zero left/top DrawQuad edges

Pages like web_tests/compositing/overflow/nested-render-surfaces-with-rotation.html
create RenderPasses (and SharedQuadStates) that have layer rects offset from
(0, 0). This seems connected to the border width of the owning DOM element.
Regardless, these edges are not clipped and DrawQuads should be anti-aliased if
they line up with the non-zero edges.

Bug: 1013735
Change-Id: Ib97e6f9a0f7f56f4926d1a209365d3c3f11a6e38
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1860098Reviewed-by: weiliangc <weiliangc@chromium.org>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Cr-Commit-Position: refs/heads/master@{#706136}

components/viz/common/quads/draw_quad.h

@@ -81,11 +81,15 @@ class VIZ_COMMON_EXPORT DrawQuad {
 
   // Is the left edge of this tile aligned with the originating layer's
   // left edge?
-  bool IsLeftEdge() const { return !rect.x(); }
+  bool IsLeftEdge() const {
+    return rect.x() == shared_quad_state->quad_layer_rect.x();
+  }
 
   // Is the top edge of this tile aligned with the originating layer's
   // top edge?
-  bool IsTopEdge() const { return !rect.y(); }
+  bool IsTopEdge() const {
+    return rect.y() == shared_quad_state->quad_layer_rect.y();
+  }
 
   // Is the right edge of this tile aligned with the originating layer's
   // right edge?