Collect host of Web Component usage to send to RAPPOR

Source/core/page/Page.cpp

Index: Source/core/page/Page.cpp
diff --git a/Source/core/page/Page.cpp b/Source/core/page/Page.cpp
index 3f27bd50248008af9a0301c357a945318d8a4105..885211d7139f47b9689fed158b0c0601fcf561ed 100644
--- a/Source/core/page/Page.cpp
+++ b/Source/core/page/Page.cpp
@@ -216,6 +216,7 @@ void Page::documentDetached(Document* document)
     m_contextMenuController->documentDetached(document);
     if (m_validationMessageClient)
         m_validationMessageClient->documentDetached(*document);
+    m_useByOriginCounter.documentDetached(*document);
 }
 
 bool Page::openedByDOM() const
@@ -546,6 +547,7 @@ void Page::didCommitLoad(LocalFrame* frame)
     if (m_mainFrame == frame) {
         frame->console().clearMessages();
         useCounter().didCommitLoad();
+        m_useByOriginCounter.updateMeasurementsAndClear();
         UserGestureIndicator::clearProcessedUserGestureSinceLoad();
     }
 }