Fix small bug with DOM Snapshot ShadowRootType.

As currently written, element nodes in Shadow DOM trees won't be
properly annotated with shadowRootType. Change an else if to a
plain if to address this. Tests fixed accordingly.

R=dgozman@chromium.org

Change-Id: Ie912de6663c8b4ed0a3638f80cd81ccbcf7e1b31
Reviewed-on: https://chromium-review.googlesource.com/951866Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Jandro Alderman <aalderman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#542285}

third_party/WebKit/LayoutTests/inspector-protocol/dom-snapshot/dom-snapshot-getSnapshot-expected.txt

@@ -595,7 +595,8 @@ Tests DOMSnapshot.getSnapshot method.
       "backendNodeId": "<number>",
       "childNodeIndexes": [
         53
-      ]
+      ],
+      "shadowRootType": "open"
     },
     {
       "nodeType": 3,
@@ -625,7 +626,8 @@ Tests DOMSnapshot.getSnapshot method.
           "value": "font-family: ahem;"
         }
       ],
-      "layoutNodeIndex": 28
+      "layoutNodeIndex": 28,
+      "shadowRootType": "open"
     },
     {
       "nodeType": 1,
@@ -635,7 +637,8 @@ Tests DOMSnapshot.getSnapshot method.
       "childNodeIndexes": [
         57
       ],
-      "layoutNodeIndex": 29
+      "layoutNodeIndex": 29,
+      "shadowRootType": "open"
     },
     {
       "nodeType": 3,

third_party/WebKit/LayoutTests/inspector-protocol/dom-snapshot/dom-snapshot-getSnapshot-input-value-expected.txt

@@ -119,7 +119,8 @@ Tests DOMSnapshot.getSnapshot method returning input values.
           "name": "name",
           "value": "user-agent-custom-assign-slot"
         }
-      ]
+      ],
+      "shadowRootType": "user-agent"
     },
     {
       "nodeType": 1,
@@ -205,6 +206,7 @@ Tests DOMSnapshot.getSnapshot method returning input values.
         16
       ],
       "layoutNodeIndex": 7,
+      "shadowRootType": "user-agent",
       "isClickable": true
     },
     {
@@ -418,6 +420,7 @@ Tests DOMSnapshot.getSnapshot method returning input values.
         31
       ],
       "layoutNodeIndex": 22,
+      "shadowRootType": "user-agent",
       "isClickable": true
     },
     {

third_party/WebKit/Source/core/inspector/InspectorDOMSnapshotAgent.cpp

@@ -279,7 +279,8 @@ int InspectorDOMSnapshotAgent::VisitNode(Node* node,
     DocumentType* doc_type = ToDocumentType(node);
     value->setPublicId(doc_type->publicId());
     value->setSystemId(doc_type->systemId());
-  } else if (node->IsInShadowTree()) {
+  }
+  if (node->IsInShadowTree()) {
     value->setShadowRootType(
         InspectorDOMAgent::GetShadowRootType(node->ContainingShadowRoot()));
   }