Expose WebPageImportanceSignals to embedder

Source/web/WebPageImportanceSignals.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "public/web/WebPageImportanceSignals.h"
+#include "public/web/WebViewClient.h"
 
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 void WebPageImportanceSignals::reset()
 {
     m_hadFormInteraction = false;
+    if (m_observer)
+        m_observer->pageImportanceSignalsChanged();
+}
+
+void WebPageImportanceSignals::setHadFormInteraction()
+{
+    m_hadFormInteraction = true;
+    if (m_observer)
+        m_observer->pageImportanceSignalsChanged();
 }
 
 void WebPageImportanceSignals::onCommitLoad()
 {
     Platform::current()->histogramEnumeration("PageImportanceSignals.HadFormInteraction.OnCommitLoad", m_hadFormInteraction, 2);
 
     reset();
 }
 
 } // namespace blink