Add test plumbing so that layout tests can query whether a compositor frame was requested

content/shell/renderer/test_runner/WebTestProxy.cpp

Index: content/shell/renderer/test_runner/WebTestProxy.cpp
diff --git a/content/shell/renderer/test_runner/WebTestProxy.cpp b/content/shell/renderer/test_runner/WebTestProxy.cpp
index 70bb6b7c95a3cb49db04dc7d3f48f33985064b17..e803c6eea8561b515bde26d449d9a3726c238280 100644
--- a/content/shell/renderer/test_runner/WebTestProxy.cpp
+++ b/content/shell/renderer/test_runner/WebTestProxy.cpp
@@ -738,6 +738,11 @@ void WebTestProxyBase::animateNow()
     }
 }
 
+bool WebTestProxyBase::isCompositorFramePending() const
+{
+    return m_animateScheduled;

[jamesr, 2014/02/11 01:47:42]

i think it'd be worth returning true if m_paintRect is nonempty as well since
that's what scheduleComposite() is tied too

[shawnsingh, 2014/02/11 02:02:06]

Done.

+}
+
 void WebTestProxyBase::show(WebNavigationPolicy)
 {
     invalidateAll();