Add coalesced KeyDown handling for arrow key scrolling.

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index 6dcc13d75e6c96c64e79e051a0a31afcbe307963..24c113765a97ae2336cbea54c39943cb36ea0b10 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -1678,6 +1678,7 @@ bool WebViewImpl::keyEventDefault(const WebKeyboardEvent& event) {
         return scrollViewWithKeyboard(keyCode, event.modifiers);
       }
       break;
+    case WebInputEvent::KeyDown:
     case WebInputEvent::RawKeyDown:
       if (event.modifiers == WebInputEvent::ControlKey) {
         switch (event.windowsKeyCode) {