[ServiceWorker] Disable the cache revalidation when the page is controlled by the ServiceWorker.

Source/core/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
@@ skipping 869 matching lines @@
     context().addAdditionalRequestHeaders(document(), request, (type == Resource::MainResource) ? FetchMainResource : FetchSubresource);
 }
 
 ResourcePtr<Resource> ResourceFetcher::createResourceForRevalidation(const FetchRequest& request, Resource* resource)
 {
     ASSERT(resource);
     ASSERT(memoryCache()->contains(resource));
     ASSERT(resource->isLoaded());
     ASSERT(resource->canUseCacheValidator());
     ASSERT(!resource->resourceToRevalidate());
+    ASSERT(!isControlledByServiceWorker());
 
     ResourceRequest revalidatingRequest(resource->resourceRequest());
     revalidatingRequest.clearHTTPReferrer();
     addAdditionalRequestHeaders(revalidatingRequest, resource->type());
 
     const AtomicString& lastModified = resource->response().httpHeaderField("Last-Modified");
     const AtomicString& eTag = resource->response().httpHeaderField("ETag");
     if (!lastModified.isEmpty() || !eTag.isEmpty()) {
         ASSERT(context().cachePolicy(document()) != CachePolicyReload);
         if (context().cachePolicy(document()) == CachePolicyRevalidate)
@@ skipping 169 matching lines @@
     // If any of the redirects in the chain to loading the resource were not cacheable, we cannot reuse our cached resource.
     if (!existingResource->canReuseRedirectChain()) {
         WTF_LOG(ResourceLoading, "ResourceFetcher::determineRevalidationPolicy reloading due to an uncacheable redirect");
         return Reload;
     }
 
     // Check if the cache headers requires us to revalidate (cache expiration for example).
     if (cachePolicy == CachePolicyRevalidate || existingResource->mustRevalidateDueToCacheHeaders()
         || request.cacheControlContainsNoCache()) {
         // See if the resource has usable ETag or Last-modified headers.
-        if (existingResource->canUseCacheValidator())
+        if (existingResource->canUseCacheValidator() && !isControlledByServiceWorker())

[nhiroki, 2014/11/05 07:38:35]

Can we have a link to the issue and a comment about why we choose 'Reload'
policy if the request is going to be handled by SW?

[horo, 2014/11/05 08:48:03]

Done.

             return Revalidate;
 
         // No, must reload.
         WTF_LOG(ResourceLoading, "ResourceFetcher::determineRevalidationPolicy reloading due to missing cache validators.");
         return Reload;
     }
 
     return Use;
 }
 
@@ skipping 470 matching lines @@
 
 void ResourceFetcher::trace(Visitor* visitor)
 {
     visitor->trace(m_document);
     visitor->trace(m_loaders);
     visitor->trace(m_multipartLoaders);
     ResourceLoaderHost::trace(visitor);
 }
 
 }