Determine prevalence of cache-control: no-store in main frame resources.

content/browser/loader/resource_dispatcher_host_impl.cc

 // Copyright (c) 2012 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.
 
 // See http://dev.chromium.org/developers/design-documents/multi-process-resource-loading
 
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 
 #include <algorithm>
 #include <set>
@@ skipping 299 matching lines @@
   return sct_status.status == net::ct::SCT_STATUS_OK;
 }
 
 webkit_blob::BlobStorageContext* GetBlobStorageContext(
     ResourceMessageFilter* filter) {
   if (!filter->blob_storage_context())
     return NULL;
   return filter->blob_storage_context()->context();
 }
 
+enum CacheStorable {
+  // A "cache-control: no-store" header was found.
+  CACHE_STORABLE_NO_STORE,
+  // No "no-store" header was found.
+  CACHE_STORABLE_STORE,
+  CACHE_STORABLE_MAX
+};
+
 }  // namespace
 
 // static
 ResourceDispatcherHost* ResourceDispatcherHost::Get() {
   return g_resource_dispatcher_host;
 }
 
 ResourceDispatcherHostImpl::ResourceDispatcherHostImpl()
     : save_file_manager_(new SaveFileManager()),
       request_id_(-1),
@@ skipping 432 matching lines @@
                                     -loader->request()->status().error());
       }
 
       int num_valid_scts = std::count_if(
           loader->request()->ssl_info().signed_certificate_timestamps.begin(),
           loader->request()->ssl_info().signed_certificate_timestamps.end(),
           IsValidatedSCT);
       UMA_HISTOGRAM_COUNTS_100(
           "Net.CertificateTransparency.MainFrameValidSCTCount", num_valid_scts);
     }
+
+    net::HttpResponseHeaders* response_headers =
+        loader->request()->response_headers();
+    if (response_headers) {
+      CacheStorable storable =
+          response_headers->HasHeaderValue("cache-control", "no-store")
+              ? CACHE_STORABLE_NO_STORE
+              : CACHE_STORABLE_STORE;

[davidben, 2014/06/11 16:28:01]

This could also just be a boolean with UMA_HISTOGRAM_BOOLEAN. The enum thing
with 0 or 1 will still work I believe.

[jkarlin, 2014/06/11 16:50:06]

True, that's simpler.  Went with BOOLEAN.

+      UMA_HISTOGRAM_ENUMERATION(
+          "Net.MainFrameStorable", storable, CACHE_STORABLE_MAX);
+    }
   } else {
     if (info->GetResourceType() == ResourceType::IMAGE) {
       UMA_HISTOGRAM_SPARSE_SLOWLY(
           "Net.ErrorCodesForImages",
           -loader->request()->status().error());
     }
     // This enumeration has "2" appended to distinguish it from older versions.
     UMA_HISTOGRAM_SPARSE_SLOWLY(
         "Net.ErrorCodesForSubresources2",
         -loader->request()->status().error());
@@ skipping 1196 matching lines @@
   if ((load_flags & net::LOAD_REPORT_RAW_HEADERS)
       && !policy->CanReadRawCookies(child_id)) {
     VLOG(1) << "Denied unauthorized request for raw headers";
     load_flags &= ~net::LOAD_REPORT_RAW_HEADERS;
   }
 
   return load_flags;
 }
 
 }  // namespace content