Throttle rendering pipeline for invisible iframes

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index c8b90f1beedfde3828fab4fb6c5a4aaddc8f64f8..28162da1d5167b1f3853da054b954736b8e20a98 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -1876,6 +1876,9 @@ void WebViewImpl::beginFrame(const WebBeginFrameArgs& frameTime)
     // FIXME: This should probably be using the local root?
     if (m_page->mainFrame()->isLocalFrame())
         PageWidgetDelegate::animate(*m_page, validFrameTime.lastFrameTimeMonotonic, *m_page->deprecatedLocalMainFrame());
+
+    // HACK: simulate the commit signal for layout tests
+    //Platform::current()->mainThread()->postTask(FROM_HERE, bind(&WebViewImpl::didCommitCompositorFrame, this));
 }
 
 void WebViewImpl::layout()
@@ -1922,6 +1925,14 @@ void WebViewImpl::paint(WebCanvas* canvas, const WebRect& rect)
     Platform::current()->histogramCustomCounts("Renderer4.SoftwarePaintMegapixPerSecond", pixelsPerSec / 1000000, 10, 210, 30);
 }
 
+void WebViewImpl::didCommitCompositorFrame()
+{
+    if (!mainFrameImpl() || !mainFrameImpl()->frameView())
+        return;
+    FrameView* view = mainFrameImpl()->frameView();
+    view->updateThrottling();
+}
+
 #if OS(ANDROID)
 void WebViewImpl::paintCompositedDeprecated(WebCanvas* canvas, const WebRect& rect)
 {