Quick fix for windows try bots flakiness.

content/shell/renderer/test_runner/web_test_proxy.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/shell/renderer/test_runner/web_test_proxy.h"
 
 #include <cctype>
 
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
@@ skipping 464 matching lines @@
 void WebTestProxyBase::SetAcceptLanguages(const std::string& accept_languages) {
   bool notify = accept_languages_ != accept_languages;
   accept_languages_ = accept_languages;
 
   if (notify)
     GetWebView()->acceptLanguagesChanged();
 }
 
 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()->
       sequenceNumber(blink::WebClipboard::Buffer());
   GetWebView()->copyImageAt(blink::WebPoint(x, y));
   if (sequence_number == blink::Platform::current()->clipboard()->
       sequenceNumber(blink::WebClipboard::Buffer())) {
     SkBitmap emptyBitmap;
     callback.Run(emptyBitmap);
     return;
@@ skipping 30 matching lines @@
   DrawSelectionRect(canvas.get());
   SkBaseDevice* device = skia::GetTopDevice(*canvas);
   const SkBitmap& bitmap = device->accessBitmap(false);
   callback.Run(bitmap);
 }
 
 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());
 
   if (test_interfaces_->GetTestRunner()->isPrinting()) {
     base::MessageLoopProxy::current()->PostTask(
         FROM_HERE,
         base::Bind(&WebTestProxyBase::CapturePixelsForPrinting,
                    base::Unretained(this),
                    callback));
     return;
@@ skipping 12 matching lines @@
   // Verify we actually composited.
   CHECK_NE(0, bitmap.info().fWidth);
   CHECK_NE(0, bitmap.info().fHeight);
   if (!callback.is_null())
     callback.Run();
 }
 
 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));
 }
 
 void WebTestProxyBase::GetScreenOrientationForTesting(
     blink::WebScreenInfo& screen_info) {
   if (!screen_orientation_client_)
     return;
   // Override screen orientation information with mock data.
@@ skipping 711 matching lines @@
   if (!push_client_.get())
     push_client_.reset(new MockWebPushClient);
   return push_client_.get();
 }
 
 blink::WebPushClient* WebTestProxyBase::GetWebPushClient() {
   return GetPushClientMock();
 }
 
 }  // namespace content