+2015-11-20 Geoffrey Garen <ggaren@apple.com>
+
+ A hung webpage pretends to be responsive if you scroll
+ https://bugs.webkit.org/show_bug.cgi?id=151518
+
+ Reviewed by Sam Weinig.
+
+ * UIProcess/WebPageProxy.cpp:
+ (WebKit::WebPageProxy::sendWheelEvent):
+ (WebKit::WebPageProxy::didReceiveEvent): Don't treat wheel events as
+ starting or stopping the responsiveness timer. Wheel events usually
+ process on the event dispatch thread, which responds even if the main
+ thread is hung.
+
+ Instead, send an out-of-band ping to the main thread to verify that
+ it is still responsive and we'll be able to paint and respond to clicks
+ after scrolling.
+
+ * UIProcess/WebProcessProxy.cpp:
+ (WebKit::WebProcessProxy::sendMainThreadPing):
+ (WebKit::WebProcessProxy::didReceiveMainThreadPing):
+ * UIProcess/WebProcessProxy.h:
+ * UIProcess/WebProcessProxy.messages.in: UI process support for pinging
+ the main thread in the web process.
+
+ * WebProcess/WebProcess.cpp:
+ (WebKit::WebProcess::mainThreadPing):
+ * WebProcess/WebProcess.h:
+ * WebProcess/WebProcess.messages.in: Web process support for responding
+ to pings.
+
2015-11-20 Simon Fraser <simon.fraser@apple.com>
Allow more buffer formats in the IOSurface pool