Fix some observatory analysis issues.

runtime/observatory/lib/src/app/page.dart

Index: runtime/observatory/lib/src/app/page.dart
diff --git a/runtime/observatory/lib/src/app/page.dart b/runtime/observatory/lib/src/app/page.dart
index 2fa3ff4d9c06860c92c265e88af400fbff3f7439..1d3c55b2c6857ec203e448f4476d8f91ee6cd526 100644
--- a/runtime/observatory/lib/src/app/page.dart
+++ b/runtime/observatory/lib/src/app/page.dart
@@ -518,7 +518,6 @@ class InspectPage extends MatchingPage {
             _reachableSizeRepository,
             _inboundReferencesRepository,
             _retainingPathRepository,

[siva, 2017/06/01 19:26:32]

why remove _objectRepository? The factory constructor of ObjectViewElement is :

  factory ObjectPoolViewElement(
      M.VM vm,
      M.IsolateRef isolate,
      M.ObjectPool pool,
      M.EventRepository events,
      M.NotificationRepository notifications,
      M.ObjectPoolRepository pools,
      M.RetainedSizeRepository retainedSizes,
      M.ReachableSizeRepository reachableSizes,
      M.InboundReferencesRepository references,
      M.RetainingPathRepository retainingPaths,
      M.ObjectRepository objects,
      {RenderingQueue queue}) {

[devoncarew, 2017/06/01 20:11:54]

This is creating a ObjectViewElement (not a ObjectPoolViewElement - created
above). I assume that ObjectViewElement is the object type we want to create
here, but it would be good to have someone familiar with the code to double
check :)

[siva, 2017/06/01 21:28:07]

Ah ok, ObjectPoolViewElement was created above.

-            _objectRepository,
             queue: app.queue)
       ];
     } else if (obj is Sentinel) {