[ServiceWorker] Don't send the UMA related headers to the ServiceWorker.

components/variations/net/variations_http_header_provider.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 "components/variations/net/variations_http_header_provider.h"
 
 #include <vector>
 
 #include "base/base64.h"
 #include "base/memory/singleton.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "components/google/core/browser/google_util.h"
 #include "components/variations/proto/client_variations.pb.h"
+#include "content/public/browser/service_worker_context.h"

[Alexei Svitkine (slow), 2014/10/27 15:09:00]

Hmm, I don't think we want to do this.

This code is in a component, partly because it's used by the iOS port of
Chromium. Which shouldn't depend on the content API.

 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 #include "net/http/http_request_headers.h"
 #include "url/gurl.h"
 
 namespace variations {
 
 namespace {
 
 const char* kSuffixesToSetHeadersFor[] = {
   ".android.com",
   ".doubleclick.com",
   ".doubleclick.net",
   ".ggpht.com",
   ".googleadservices.com",
   ".googleapis.com",
   ".googlesyndication.com",
   ".googleusercontent.com",
   ".googlevideo.com",
   ".gstatic.com",
   ".ytimg.com",
 };
 
+const char kChromeUMAEnabled[] = "X-Chrome-UMA-Enabled";
+const char kClientData[] = "X-Client-Data";
+
 }  // namespace
 
 VariationsHttpHeaderProvider* VariationsHttpHeaderProvider::GetInstance() {
   return Singleton<VariationsHttpHeaderProvider>::get();
 }
 
 void VariationsHttpHeaderProvider::AppendHeaders(
     const GURL& url,
     bool incognito,
     bool uma_enabled,
     net::HttpRequestHeaders* headers) {
   // Note the criteria for attaching client experiment headers:
   // 1. We only transmit to Google owned domains which can evaluate experiments.
   //    1a. These include hosts which have a standard postfix such as:
   //         *.doubleclick.net or *.googlesyndication.com or
   //         exactly www.googleadservices.com or
   //         international TLD domains *.google.<TLD> or *.youtube.<TLD>.
   // 2. Only transmit for non-Incognito profiles.
   // 3. For the X-Chrome-UMA-Enabled bit, only set it if UMA is in fact enabled
   //    for this install of Chrome.
   // 4. For the X-Client-Data header, only include non-empty variation IDs.
   if (incognito || !ShouldAppendHeaders(url))
     return;
 
   if (uma_enabled)
-    headers->SetHeaderIfMissing("X-Chrome-UMA-Enabled", "1");
+    headers->SetHeaderIfMissing(kChromeUMAEnabled, "1");
 
   // Lazily initialize the header, if not already done, before attempting to
   // transmit it.
   InitVariationIDsCacheIfNeeded();
 
   std::string variation_ids_header_copy;
   {
     base::AutoLock scoped_lock(lock_);
     variation_ids_header_copy = variation_ids_header_;
   }
 
   if (!variation_ids_header_copy.empty()) {
     // Note that prior to M33 this header was named X-Chrome-Variations.
-    headers->SetHeaderIfMissing("X-Client-Data",
-                                variation_ids_header_copy);
+    headers->SetHeaderIfMissing(kClientData, variation_ids_header_copy);
   }
 }
 
 bool VariationsHttpHeaderProvider::SetDefaultVariationIds(
     const std::string& variation_ids) {
   default_variation_ids_set_.clear();
   default_trigger_id_set_.clear();
   std::vector<std::string> entries;
   base::SplitString(variation_ids, ',', &entries);
   for (std::vector<std::string>::const_iterator it = entries.begin();
@@ skipping 16 matching lines @@
     if (trigger_id)
       default_trigger_id_set_.insert(variation_id);
     else
       default_variation_ids_set_.insert(variation_id);
   }
   return true;
 }
 
 VariationsHttpHeaderProvider::VariationsHttpHeaderProvider()
     : variation_ids_cache_initialized_(false) {
+  content::ServiceWorkerContext::AddExcludedHeaderNameForFetchEvent(

[Alexei Svitkine (slow), 2014/10/27 15:09:00]

Since this code can't depend on content/ per my comment above, my suggestion is
to expose a getter from this class for the headers. Since this class is a
singleton, then some initialization code in chrome/browser can query that getter
and call the ServiceWorkerContext::AddExcludeHeaderNameForFetchEvent() on them.

[michaeln, 2014/10/27 21:50:26]

Sounds reasonable, maybe the ChromeResourceDispatcherHostDelegate could arrange
to do that initialization on the IO thread.

[horo, 2014/10/28 02:35:05]

Done.

+      kChromeUMAEnabled);
+  content::ServiceWorkerContext::AddExcludedHeaderNameForFetchEvent(
+      kClientData);
 }
 
 VariationsHttpHeaderProvider::~VariationsHttpHeaderProvider() {
 }
 
 void VariationsHttpHeaderProvider::OnFieldTrialGroupFinalized(
     const std::string& trial_name,
     const std::string& group_name) {
   VariationID new_id =
       GetGoogleVariationID(GOOGLE_WEB_PROPERTIES, trial_name, group_name);
@@ skipping 126 matching lines @@
   for (size_t i = 0; i < arraysize(kSuffixesToSetHeadersFor); ++i) {
     if (EndsWith(host, kSuffixesToSetHeadersFor[i], false))
       return true;
   }
 
   return google_util::IsYoutubeDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
                                          google_util::ALLOW_NON_STANDARD_PORTS);
 }
 
 }  // namespace variations