Flash players weren't receiving mouse wheel events.

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

 /*
  * Copyright (C) 2012 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 14 matching lines @@
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "public/web/WebPluginContainer.h"
 
 #include "core/dom/Element.h"
 #include "core/events/KeyboardEvent.h"
+#include "core/frame/EventHandlerRegistry.h"
+#include "core/frame/FrameHost.h"
 #include "core/layout/LayoutObject.h"
+#include "core/page/Page.h"
 #include "platform/PlatformEvent.h"
 #include "platform/PlatformKeyboardEvent.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/CullRect.h"
 #include "platform/graphics/paint/ForeignLayerDisplayItem.h"
 #include "platform/graphics/paint/PaintController.h"
 #include "platform/testing/URLTestHelpers.h"
 #include "platform/testing/UnitTestHelpers.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebClipboard.h"
@@ skipping 577 matching lines @@
     paintController->commitNewDisplayItems();
 
     const auto& displayItems = paintController->paintArtifact().getDisplayItemList();
     ASSERT_EQ(1u, displayItems.size());
     EXPECT_EQ(element->layoutObject(), &displayItems[0].client());
     ASSERT_EQ(DisplayItem::ForeignLayerPlugin, displayItems[0].getType());
     const auto& foreignLayerDisplayItem = static_cast<const ForeignLayerDisplayItem&>(displayItems[0]);
     EXPECT_EQ(plugin->getWebLayer()->ccLayer(), foreignLayerDisplayItem.layer());
 }
 
+TEST_F(WebPluginContainerTest, NeedsWheelEvents)
+{
+    URLTestHelpers::registerMockedURLFromBaseURL(
+        WebString::fromUTF8(m_baseURL.c_str()),
+        WebString::fromUTF8("plugin_container.html"));
+    TestPluginWebFrameClient pluginWebFrameClient; // Must outlive webViewHelper
+    FrameTestHelpers::WebViewHelper webViewHelper;
+    WebViewImpl* webView = webViewHelper.initializeAndLoad(m_baseURL + "plugin_container.html", true, &pluginWebFrameClient);
+    ASSERT(webView);
+    webView->settings()->setPluginsEnabled(true);
+    webView->resize(WebSize(300, 300));
+    webView->updateAllLifecyclePhases();
+    runPendingTasks();
+
+    WebElement pluginContainerOneElement = webView->mainFrame()->document().getElementById(WebString::fromUTF8("translated-plugin"));
+    pluginContainerOneElement.pluginContainer()->setWantsWheelEvents(true);
+
+    runPendingTasks();
+    EXPECT_TRUE(webView->page()->frameHost().eventHandlerRegistry().hasEventHandlers(EventHandlerRegistry::WheelEventBlocking));
+}
+
 } // namespace blink