Plumb gesture source value through Blink.

third_party/WebKit/Source/web/tests/TopControlsTest.cpp

 /*
  * Copyright (C) 2015 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 78 matching lines @@
 
     void registerMockedHttpURLLoad(const std::string& fileName)
     {
         URLTestHelpers::registerMockedURLFromBaseURL(WebString::fromUTF8(m_baseURL.c_str()), WebString::fromUTF8(fileName.c_str()));
     }
 
     WebGestureEvent generateEvent(WebInputEvent::Type type, int deltaX = 0, int deltaY = 0)
     {
         WebGestureEvent event;
         event.type = type;
+        event.sourceDevice = WebGestureDeviceTouchscreen;
         event.x = 100;
         event.y = 100;
         if (type == WebInputEvent::GestureScrollUpdate) {
             event.data.scrollUpdate.deltaX = deltaX;
             event.data.scrollUpdate.deltaY = deltaY;
         }
         return event;
     }
 
     void verticalScroll(float deltaY)
@@ skipping 435 matching lines @@
     verticalScroll(50.f);
     EXPECT_FLOAT_EQ(50, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 90), frame()->view()->scrollPosition());
 
     verticalScroll(-50.f);
     EXPECT_FLOAT_EQ(0, webView->topControls().contentOffset());
     EXPECT_POINT_EQ(IntPoint(0, 90), frame()->view()->scrollPosition());
 }
 
 } // namespace blink