DevTools: Fix and re-enable scope tests

This CL fixes tests that will be broken by
https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/1889351

Bug: 963183
Change-Id: I3af9e90385d38fd9f9dce6c8107de41afda03db3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1811968Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Jack Lynch <jalyn@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#721288}

third_party/blink/web_tests/TestExpectations

@@ -5939,10 +5939,6 @@ crbug.com/1021407 [ Retina Release ] virtual/audio-service/media/video-controls-
 crbug.com/1021407 [ Mac10.11 ] virtual/audio-service/media/controls/video-overlay-cast-dark-rendering.html [ Pass Failure ]
 crbug.com/1021407 [ Mac10.11 ] media/controls/video-overlay-cast-dark-rendering.html [ Pass Failure ]
 
-# Temporarily disabled to land scope changes in DevTools
-crbug.com/963183 http/tests/devtools/sources/debugger-pause/set-return-value.js [ Pass Failure ]
-crbug.com/963183 http/tests/devtools/sources/debugger/debugger-proto-property.js [ Pass Failure ]
-
 crbug.com/892983 external/wpt/css/css-pseudo/first-line-with-before-after.html [ Failure ]
 
 # Sheriff 2019-11-15

third_party/blink/web_tests/http/tests/devtools/sources/debugger-pause/set-return-value.js

@@ -18,7 +18,7 @@
   let sidebarUpdated = TestRunner.addSnifferPromise(
         Sources.ScopeChainSidebarPane.prototype, '_sidebarPaneUpdatedForTest');
   await Promise.all([SourcesTestRunner.runTestFunctionAndWaitUntilPausedPromise(), sidebarUpdated]);
-  let localScope = SourcesTestRunner.scopeChainSections()[0].objectTreeElement();
+  let localScope = SourcesTestRunner.scopeChainSections()[0];
 
   TestRunner.addResult('Dump current');
   await new Promise(resolve => SourcesTestRunner.expandProperties([localScope, ['Return value']], resolve));

third_party/blink/web_tests/http/tests/devtools/sources/debugger/debugger-proto-property.js

@@ -33,7 +33,7 @@
   }
 
   function onSidebarRendered() {
-    var localScope = SourcesTestRunner.scopeChainSections()[0].objectTreeElement();
+    var localScope = SourcesTestRunner.scopeChainSections()[0];
     var properties = [
       localScope, ['o', '__proto__', '__proto__'], localScope,
       ['d', '__proto__', '__proto__', '__proto__', '__proto__', '__proto__']