Evict resources from memory cache after running rendering test.

third_party/WebKit/Source/core/layout/LayoutTestHelper.cpp

 // 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 "core/layout/LayoutTestHelper.h"
 
+#include "core/fetch/MemoryCache.h"
 #include "core/frame/FrameHost.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "platform/scroll/ScrollbarTheme.h"
 
 namespace blink {
 
 RenderingTest::RenderingTest(FrameLoaderClient* frameLoaderClient)
     : m_frameLoaderClient(frameLoaderClient) { }
 
 void RenderingTest::SetUp()
@@ skipping 18 matching lines @@
     if (m_subframe) {
         m_subframe->detach(FrameDetachType::Remove);
         static_cast<SingleChildFrameLoaderClient*>(document().frame()->client())->setChild(nullptr);
         document().frame()->host()->decrementSubframeCount();
     }
 
     // We need to destroy most of the Blink structure here because derived tests may restore
     // RuntimeEnabledFeatures setting during teardown, which happens before our destructor
     // getting invoked, breaking the assumption that REF can't change during Blink lifetime.
     m_pageHolder = nullptr;
+
+    // Clear memory cache, otherwise we can leak pruned resources.
+    memoryCache()->evictResources();

[haraken, 2016/08/26 00:58:49]

Just help me understand: What's a difference between prune() and
evictResource()? Is calling prune() not enough to release the underlying
Resources?

 }
 
 Document& RenderingTest::setupChildIframe(const AtomicString& iframeElementId, const String& htmlContentOfIframe)
 {
     // TODO(pdr): This should be refactored to share code with the actual setup
     // instead of partially duplicating it here (e.g., LocalFrame::createView).
     HTMLIFrameElement& iframe = *toHTMLIFrameElement(document().getElementById(iframeElementId));
     m_childFrameLoaderClient = FrameLoaderClientWithParent::create(document().frame());
     m_subframe = LocalFrame::create(m_childFrameLoaderClient.get(), document().frame()->host(), &iframe);
     m_subframe->setView(FrameView::create(m_subframe.get(), IntSize(500, 500)));
     m_subframe->init();
     m_subframe->view()->setParentVisible(true);
     m_subframe->view()->setSelfVisible(true);
     iframe.setWidget(m_subframe->view());
     static_cast<SingleChildFrameLoaderClient*>(document().frame()->client())->setChild(m_subframe.get());
     document().frame()->host()->incrementSubframeCount();
     Document& frameDocument = *iframe.contentDocument();
 
     frameDocument.setBaseURLOverride(KURL(ParsedURLString, "http://test.com"));
     frameDocument.body()->setInnerHTML(htmlContentOfIframe, ASSERT_NO_EXCEPTION);
     return frameDocument;
 }
 
 } // namespace blink