Refactor VariationsHttpHeaderProvider.

components/variations/net/variations_http_headers.cc

+// Copyright 2015 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_headers.h"
+
+#include "base/strings/string_util.h"
+#include "components/google/core/browser/google_util.h"
+#include "components/variations/variations_http_header_provider.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
+
+void AppendVariationHeaders(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 || !internal::ShouldAppendVariationHeaders(url))
+    return;
+
+  if (uma_enabled)
+    headers->SetHeaderIfMissing(kChromeUMAEnabled, "1");
+
+  const std::string variation_ids_header =
+      VariationsHttpHeaderProvider::GetInstance()->GetClientDataHeader();
+  if (!variation_ids_header.empty()) {
+    // Note that prior to M33 this header was named X-Chrome-Variations.
+    headers->SetHeaderIfMissing(kClientData, variation_ids_header);
+  }
+}
+
+std::set<std::string> GetVariationHeaderNames() {
+  std::set<std::string> headers;
+  headers.insert(kChromeUMAEnabled);
+  headers.insert(kClientData);
+  return headers;
+}
+
+namespace internal {
+
+// static
+bool ShouldAppendVariationHeaders(const GURL& url) {
+  if (google_util::IsGoogleDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
+                                     google_util::ALLOW_NON_STANDARD_PORTS)) {
+    return true;
+  }
+
+  if (!url.is_valid() || !url.SchemeIsHTTPOrHTTPS())
+    return false;
+
+  // Some domains don't have international TLD extensions, so testing for them
+  // is very straight forward.
+  const std::string host = url.host();
+  for (size_t i = 0; i < arraysize(kSuffixesToSetHeadersFor); ++i) {
+    if (base::EndsWith(host, kSuffixesToSetHeadersFor[i],
+                       base::CompareCase::INSENSITIVE_ASCII))
+      return true;
+  }
+
+  return google_util::IsYoutubeDomainUrl(url, google_util::ALLOW_SUBDOMAIN,
+                                         google_util::ALLOW_NON_STANDARD_PORTS);
+}
+
+}  // namespace internal
+
+}  // namespace variations