Enforce SafetyMode for YouTube if prefs::kForceSafeSearch is on.

chrome/browser/net/chrome_network_delegate.cc

Index: chrome/browser/net/chrome_network_delegate.cc
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index 6558ae123a8d01eac386242f1b1d44222e8e392a..1ce96d656e2d04a61aeded7fb843772cde907b65 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -17,6 +17,8 @@
 #include "base/prefs/pref_service.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
@@ -161,6 +163,67 @@ void ForceGoogleSafeSearchCallbackWrapper(
   callback.Run(rv);
 }
 
+const char kYoutubePrefCookieName[] = "PREF";

[battre, 2014/07/07 09:00:06]

What do you think of moving the youtube and safebrowsing code into a separate
file? This manipulation of bits feels like very grungy code.

Please add a unit test.

[Marc Treib, 2014/07/07 16:06:46]

It is grungy :-/
I moved the code into new safe_search_util.h/cc files.
Done.

+// Youtube pref flags are stored in bit masks of 31 bits each, called "f1",
+// "f2" etc. The Safety Mode flag is bit 58, so bit 27 in "f2".
+const char kYoutubePrefCookieSafetyModeFlagsEntryName[] = "f2";
+const int kYoutubePrefCookieSafetyModeFlagsEntryValue = (1 << 27);
+const char kYoutubePrefCookieFlagsValueFormat[] = "%x";
+
+bool IsYoutubePrefCookie(const std::pair<std::string, std::string>& cookie) {
+  return cookie.first == kYoutubePrefCookieName;
+}
+
+bool IsYoutubePrefCookieSafetyModeFlagsEntry(
+    const std::pair<std::string, std::string>& pref_entry) {
+  return pref_entry.first == kYoutubePrefCookieSafetyModeFlagsEntryName;
+}
+
+// If |request| is a request to Youtube, enforces Youtube's Safety Mode by
+// adding/modifying Youtube's PrefCookie header.
+void ForceYoutubeSafetyMode(const net::URLRequest* request,
+                            net::HttpRequestHeaders* headers) {

[battre, 2014/07/07 09:00:06]

Could you add more newlines into this function and document what the blocks are
doing?

[Marc Treib, 2014/07/07 16:06:46]

Done.

+  if (!google_util::IsYoutubeDomainUrl(
+          request->url(),
+          google_util::ALLOW_SUBDOMAIN,
+          google_util::DISALLOW_NON_STANDARD_PORTS))
+    return;
+
+  std::string cookie_string;
+  headers->GetHeader(base::StringPiece(net::HttpRequestHeaders::kCookie),
+                     &cookie_string);
+  base::StringPairs cookies;
+  base::SplitStringIntoKeyValuePairs(cookie_string, '=', ';', &cookies);
+  base::StringPairs::iterator pref_it =
+      std::find_if(cookies.begin(), cookies.end(), IsYoutubePrefCookie);
+  if (pref_it == cookies.end()) {
+    cookies.push_back(std::make_pair(std::string(kYoutubePrefCookieName),
+                                     std::string()));
+    pref_it = cookies.end() - 1;
+  }
+  base::StringPairs pref_values;
+  base::SplitStringIntoKeyValuePairs(pref_it->second, '=', '&', &pref_values);
+  base::StringPairs::iterator flag_it =
+      std::find_if(pref_values.begin(), pref_values.end(),
+                   IsYoutubePrefCookieSafetyModeFlagsEntry);
+  int flag_value = 0;
+  if (flag_it == pref_values.end()) {
+    pref_values.push_back(
+        std::make_pair(std::string(kYoutubePrefCookieSafetyModeFlagsEntryName),
+                       std::string()));
+    flag_it = pref_values.end() - 1;
+  } else {
+    base::HexStringToInt(base::StringPiece(flag_it->second), &flag_value);
+  }
+  flag_value |= kYoutubePrefCookieSafetyModeFlagsEntryValue;
+  flag_it->second =
+      base::StringPrintf(kYoutubePrefCookieFlagsValueFormat, flag_value);
+  pref_it->second = JoinStringKeyValuePairs(pref_values, '=', '&');
+  cookie_string = JoinStringKeyValuePairs(cookies, '=', ';');
+  headers->SetHeader(base::StringPiece(net::HttpRequestHeaders::kCookie),
+                     base::StringPiece(cookie_string));
+}
+
 void UpdateContentLengthPrefs(
     int received_content_length,
     int original_content_length,
@@ -478,6 +541,11 @@ int ChromeNetworkDelegate::OnBeforeSendHeaders(
     net::URLRequest* request,
     const net::CompletionCallback& callback,
     net::HttpRequestHeaders* headers) {
+  bool force_safe_search = force_google_safe_search_ &&
+                           force_google_safe_search_->GetValue();
+  if (force_safe_search)
+    ForceYoutubeSafetyMode(request, headers);
+
   TRACE_EVENT_ASYNC_STEP_PAST0("net", "URLRequest", request, "SendRequest");
   return extensions_delegate_->OnBeforeSendHeaders(request, callback, headers);
 }