VizDevTools: Observing static Surface tree

Builds the Surface tree considering Surfaces that correspond to
RootFrameSinks and detached Surfaces as root Surfaces. All of these are
attached to RootElement.

Bug:816802

[email protected]

Change-Id: I74d11ddb0fed9dc31712dc6e98cf20e936856400
Reviewed-on: https://chromium-review.googlesource.com/1185964
Commit-Queue: Yi Xu <[email protected]>
Reviewed-by: Fady Samuel <[email protected]>
Cr-Commit-Position: refs/heads/master@{#589302}
diff --git a/components/ui_devtools/ui_element.h b/components/ui_devtools/ui_element.h
index 6cd260a..c4fd3131 100644
--- a/components/ui_devtools/ui_element.h
+++ b/components/ui_devtools/ui_element.h
@@ -23,7 +23,7 @@
 }
 
 // UIElement type.
-enum UIElementType { WINDOW, WIDGET, VIEW, ROOT, FRAMESINK };
+enum UIElementType { WINDOW, WIDGET, VIEW, ROOT, FRAMESINK, SURFACE };
 
 class UI_DEVTOOLS_EXPORT UIElement {
  public: