Quick fix for windows try bots flakiness.

content/shell/renderer/test_runner/web_test_proxy.cc

Index: content/shell/renderer/test_runner/web_test_proxy.cc
diff --git a/content/shell/renderer/test_runner/web_test_proxy.cc b/content/shell/renderer/test_runner/web_test_proxy.cc
index 983c864de63e11ac90444219d6c8c377dd1f7606..cf1f033471d349ccbe615e110599212c9e1f94a4 100644
--- a/content/shell/renderer/test_runner/web_test_proxy.cc
+++ b/content/shell/renderer/test_runner/web_test_proxy.cc
@@ -482,6 +482,11 @@ void WebTestProxyBase::SetAcceptLanguages(const std::string& accept_languages) {
 
 void WebTestProxyBase::CopyImageAtAndCapturePixels(
     int x, int y, const base::Callback<void(const SkBitmap&)>& callback) {
+  // It may happen that there is a scheduled animation and
+  // no rootGraphicsLayer yet. If so we would run it right now. Otherwise
+  // isAcceleratedCompositingActive will return false;
+  AnimateNow();

[danakj, 2014/09/18 15:33:41]

I think we need to fix WebViewImpl/blink, not just the test harness.

+
   DCHECK(web_widget_->isAcceleratedCompositingActive());
   DCHECK(!callback.is_null());
   uint64_t sequence_number =  blink::Platform::current()->clipboard()->
@@ -532,6 +537,11 @@ void WebTestProxyBase::CapturePixelsAsync(
     const base::Callback<void(const SkBitmap&)>& callback) {
   TRACE_EVENT0("shell", "WebTestProxyBase::CapturePixelsAsync");
 
+  // It may happen that there is a scheduled animation and
+  // no rootGraphicsLayer yet. If so we would run it right now. Otherwise
+  // isAcceleratedCompositingActive will return false;
+  AnimateNow();
+
   DCHECK(web_widget_->isAcceleratedCompositingActive());
   DCHECK(!callback.is_null());
 
@@ -564,6 +574,11 @@ void WebTestProxyBase::DidDisplayAsync(const base::Closure& callback,
 void WebTestProxyBase::DisplayAsyncThen(const base::Closure& callback) {
   TRACE_EVENT0("shell", "WebTestProxyBase::DisplayAsyncThen");
 
+  // It may happen that there is a scheduled animation and
+  // no rootGraphicsLayer yet. If so we would run it right now. Otherwise
+  // isAcceleratedCompositingActive will return false;
+  AnimateNow();
+
   CHECK(web_widget_->isAcceleratedCompositingActive());
   CapturePixelsAsync(base::Bind(
       &WebTestProxyBase::DidDisplayAsync, base::Unretained(this), callback));