DevTools: SVG Icons

This switches our icons to use svg instead of png. It replaces
the png optimizer with an svg optimizer.

Change-Id: I63f8de9059502ab952d39bbefe5da1f6d4708d37
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1643403
Commit-Queue: Joel Einbinder <[email protected]>
Reviewed-by: Erik Luo <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#667807}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 56a647b2510baf3b314fab1130dbe08c191c9072
diff --git a/front_end/ui/treeoutline.js b/front_end/ui/treeoutline.js
index 2a722ff..5b95a5d 100644
--- a/front_end/ui/treeoutline.js
+++ b/front_end/ui/treeoutline.js
@@ -1282,9 +1282,6 @@
 
 (function() {
 const img = new Image();
-if (window.devicePixelRatio > 1)
-  img.src = 'Images/treeoutlineTriangles_2x.png';
-else
-  img.src = 'Images/treeoutlineTriangles.png';
+img.src = 'Images/treeoutlineTriangles.svg';
 UI.TreeElement._imagePreload = img;
 })();