[WIP] WebFonts cache-aware timeout adaption

third_party/WebKit/Source/platform/network/ResourceRequest.cpp

Index: third_party/WebKit/Source/platform/network/ResourceRequest.cpp
diff --git a/third_party/WebKit/Source/platform/network/ResourceRequest.cpp b/third_party/WebKit/Source/platform/network/ResourceRequest.cpp
index 4d264c050380bd298bae9b62e29b41ddb7e3be49..05c5525b82cba65a89ad1b9e0627fd02369dd6f5 100644
--- a/third_party/WebKit/Source/platform/network/ResourceRequest.cpp
+++ b/third_party/WebKit/Source/platform/network/ResourceRequest.cpp
@@ -88,6 +88,8 @@ ResourceRequest::ResourceRequest(CrossThreadResourceRequestData* data)
   m_uiStartTime = data->m_uiStartTime;
   m_isExternalRequest = data->m_isExternalRequest;
   m_inputPerfMetricReportPolicy = data->m_inputPerfMetricReportPolicy;
+  m_isCacheAwareLoadingActivated = data->m_isCacheAwareLoadingActivated;
+  m_savedCachePolicy = data->m_savedCachePolicy;
   m_redirectStatus = data->m_redirectStatus;
 }
 
@@ -136,6 +138,8 @@ std::unique_ptr<CrossThreadResourceRequestData> ResourceRequest::copyData()
   data->m_uiStartTime = m_uiStartTime;
   data->m_isExternalRequest = m_isExternalRequest;
   data->m_inputPerfMetricReportPolicy = m_inputPerfMetricReportPolicy;
+  data->m_isCacheAwareLoadingActivated = m_isCacheAwareLoadingActivated;
+  data->m_savedCachePolicy = m_savedCachePolicy;
   data->m_redirectStatus = m_redirectStatus;
   return data;
 }
@@ -169,7 +173,17 @@ WebCachePolicy ResourceRequest::getCachePolicy() const {
 }
 
 void ResourceRequest::setCachePolicy(WebCachePolicy cachePolicy) {
-  m_cachePolicy = cachePolicy;
+  // TODO(shaochuan): This may be called after cache-aware loading is activated,
+  // deactivate if cache policy is set to unsupported value. Remove after cache
+  // policy is only set before cache-aware loading activation. crbug.com/632580
+  if (m_isCacheAwareLoadingActivated &&
+      !isCacheAwareLoadingSupported(cachePolicy))
+    deactivateCacheAwareLoading();
+
+  if (m_isCacheAwareLoadingActivated)
+    m_savedCachePolicy = cachePolicy;
+  else
+    m_cachePolicy = cachePolicy;
 }
 
 double ResourceRequest::timeoutInterval() const {
@@ -392,6 +406,38 @@ bool ResourceRequest::hasCacheValidatorFields() const {
          !m_httpHeaderFields.get(HTTPNames::ETag).isEmpty();
 }
 
+bool ResourceRequest::isCacheAwareLoadingSupported(WebCachePolicy cachePolicy) {
+  switch (cachePolicy) {
+    case WebCachePolicy::BypassingCache:
+    case WebCachePolicy::ReturnCacheDataDontLoad:
+      return false;
+    case WebCachePolicy::UseProtocolCachePolicy:
+    case WebCachePolicy::ValidatingCacheData:
+    case WebCachePolicy::ReturnCacheDataElseLoad:
+      break;
+  }
+  return true;
+}
+
+void ResourceRequest::mayActivateCacheAwareLoading() {
+  DCHECK(!m_isCacheAwareLoadingActivated);
+  if (!isCacheAwareLoadingSupported(m_cachePolicy))
+    return;
+
+  m_savedCachePolicy = m_cachePolicy;
+  // TODO(shaochuan): Stale data may be retrieved with this flag. Switch to new
+  // flag to load from disk cache with validation when available in net.
+  // crbug.com/652649
+  m_cachePolicy = WebCachePolicy::ReturnCacheDataDontLoad;
+  m_isCacheAwareLoadingActivated = true;
+}
+
+void ResourceRequest::deactivateCacheAwareLoading() {
+  DCHECK(m_isCacheAwareLoadingActivated);
+  m_cachePolicy = m_savedCachePolicy;
+  m_isCacheAwareLoadingActivated = false;
+}
+
 void ResourceRequest::initialize(const KURL& url) {
   m_url = url;
   m_cachePolicy = WebCachePolicy::UseProtocolCachePolicy;
@@ -424,6 +470,8 @@ void ResourceRequest::initialize(const KURL& url) {
   m_inputPerfMetricReportPolicy = InputToLoadPerfMetricReportPolicy::NoReport;
   m_redirectStatus = RedirectStatus::NoRedirect;
   m_requestorOrigin = SecurityOrigin::createUnique();
+  m_isCacheAwareLoadingActivated = false;
+  m_savedCachePolicy = WebCachePolicy::UseProtocolCachePolicy;
 }
 
 }  // namespace blink