Visual viewport API initial implementation.

third_party/WebKit/Source/core/dom/Document.cpp

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 9d85b6563e4b8cca9fe8f99838c6e15ffeae7a32..0c9b8d2fcedc37c6fda618e7f159cd26d6576b89 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1230,6 +1230,18 @@ Element* Document::scrollingElement()
     return body();
 }
 
+VisualViewport* Document::visualViewport()
+{
+    if (FrameHost* host = frameHost())
+        return &host->visualViewport();
+    return nullptr;
+}
+
+void Document::dispatchVisualViewportChangedEvent()
+{
+    dispatchEvent(Event::create(EventTypeNames::visualviewportchanged));
+}
+
 /*
  * Performs three operations:
  *  1. Convert control characters to spaces