Revert of network_time_tracker: add temporary time protocol.

components/network_time/network_time_tracker.cc

Index: components/network_time/network_time_tracker.cc
diff --git a/components/network_time/network_time_tracker.cc b/components/network_time/network_time_tracker.cc
index 3a17ba87c2094d208105addf565197e4f7276502..73f66ddfbd710706e5b75cb8379013414e49f570 100644
--- a/components/network_time/network_time_tracker.cc
+++ b/components/network_time/network_time_tracker.cc
@@ -7,31 +7,18 @@
 #include <stdint.h>
 #include <utility>
 
-#include "base/feature_list.h"
 #include "base/i18n/time_formatting.h"
-#include "base/json/json_reader.h"
 #include "base/logging.h"
-#include "base/message_loop/message_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/tick_clock.h"
 #include "build/build_config.h"
-#include "components/client_update_protocol/ecdsa.h"
 #include "components/network_time/network_time_pref_names.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/pref_service.h"
-#include "net/base/load_flags.h"
-#include "net/base/net_errors.h"
-#include "net/http/http_response_headers.h"
-#include "net/url_request/url_fetcher.h"
-#include "net/url_request/url_fetcher_response_writer.h"
-#include "net/url_request/url_request_context_getter.h"
 
 namespace network_time {
 
 namespace {
-
-// Minimum number of minutes between time queries.
-const uint32_t kMinimumQueryDelayMinutes = 60;
 
 // Number of time measurements performed in a given network time calculation.
 const uint32_t kNumTimeMeasurements = 7;
@@ -54,61 +41,6 @@
 // Name of a pref that stores the network time via |ToJsTime|.
 const char kPrefNetworkTime[] = "network";
 
-// Time server's maximum allowable clock skew, in seconds.  (This is a property
-// of the time server that we happen to know.  It's unlikely that it would ever
-// be that badly wrong, but all the same it's included here to document the very
-// rough nature of the time service provided by this class.)
-const uint32_t kTimeServerMaxSkewSeconds = 10;
-
-const char kTimeServiceURL[] = "http://clients2.google.com/time/1/current";
-
-// Finch feature that enables network time service querying.
-const base::Feature kNetworkTimeServiceQuerying{
-    "NetworkTimeServiceQuerying", base::FEATURE_DISABLED_BY_DEFAULT};
-
-// This is an ECDSA prime256v1 named-curve key.
-const int kKeyVersion = 1;
-const uint8_t kKeyPubBytes[] = {
-    0x30, 0x59, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x02,
-    0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03, 0x01, 0x07, 0x03,
-    0x42, 0x00, 0x04, 0xeb, 0xd8, 0xad, 0x0b, 0x8f, 0x75, 0xe8, 0x84, 0x36,
-    0x23, 0x48, 0x14, 0x24, 0xd3, 0x93, 0x42, 0x25, 0x43, 0xc1, 0xde, 0x36,
-    0x29, 0xc6, 0x95, 0xca, 0xeb, 0x28, 0x85, 0xff, 0x09, 0xdc, 0x08, 0xec,
-    0x45, 0x74, 0x6e, 0x4b, 0xc3, 0xa5, 0xfd, 0x8a, 0x2f, 0x02, 0xa0, 0x4b,
-    0xc3, 0xc6, 0xa4, 0x7b, 0xa4, 0x41, 0xfc, 0xa7, 0x02, 0x54, 0xab, 0xe3,
-    0xe4, 0xb1, 0x00, 0xf5, 0xd5, 0x09, 0x11};
-
-std::string GetServerProof(const net::URLFetcher* source) {
-  const net::HttpResponseHeaders* response_headers =
-      source->GetResponseHeaders();
-  if (!response_headers) {
-    return std::string();
-  }
-  std::string proof;
-  return response_headers->EnumerateHeader(nullptr, "x-cup-server-proof",
-                                           &proof)
-             ? proof
-             : std::string();
-}
-
-// Limits the amount of data that will be buffered from the server's response.
-class SizeLimitingStringWriter : public net::URLFetcherStringWriter {
- public:
-  SizeLimitingStringWriter(size_t limit) : limit_(limit) {}
-
-  int Write(net::IOBuffer* buffer,
-            int num_bytes,
-            const net::CompletionCallback& callback) override {
-    if (data().length() + num_bytes > limit_) {
-      return net::ERR_FILE_TOO_BIG;
-    }
-    return net::URLFetcherStringWriter::Write(buffer, num_bytes, callback);
-  }
-
- private:
-  size_t limit_;
-};
-
 }  // namespace
 
 // static
@@ -120,13 +52,8 @@
 NetworkTimeTracker::NetworkTimeTracker(
     std::unique_ptr<base::Clock> clock,
     std::unique_ptr<base::TickClock> tick_clock,
-    PrefService* pref_service,
-    scoped_refptr<net::URLRequestContextGetter> getter)
-    : server_url_(kTimeServiceURL),
-      max_response_size_(1024),
-      getter_(std::move(getter)),
-      loop_(nullptr),
-      clock_(std::move(clock)),
+    PrefService* pref_service)
+    : clock_(std::move(clock)),
       tick_clock_(std::move(tick_clock)),
       pref_service_(pref_service) {
   const base::DictionaryValue* time_mapping =
@@ -156,13 +83,6 @@
     pref_service_->ClearPref(prefs::kNetworkTimeMapping);
     network_time_at_last_measurement_ = base::Time();  // Reset.
   }
-
-  base::StringPiece public_key = {reinterpret_cast<const char*>(kKeyPubBytes),
-                                  sizeof(kKeyPubBytes)};
-  query_signer_ =
-      client_update_protocol::Ecdsa::Create(kKeyVersion, public_key);
-
-  QueueTimeQuery(base::TimeDelta::FromMinutes(kMinimumQueryDelayMinutes));
 }
 
 NetworkTimeTracker::~NetworkTimeTracker() {
@@ -212,40 +132,6 @@
   time_mapping.SetDouble(kPrefNetworkTime,
       network_time_at_last_measurement_.ToJsTime());
   pref_service_->Set(prefs::kNetworkTimeMapping, time_mapping);
-
-  // Calls to update the network time can (as of this writing) come from various
-  // sources, e.g. organically from Omaha update checks.  In that even, we may
-  // as well delay the next time server query.  If |UpdateNetworkTime| is ever
-  // made into a private method, this can be removed.
-  query_timer_.Reset();
-}
-
-void NetworkTimeTracker::SetTimeServerURLForTesting(const GURL& url) {
-  server_url_ = url;
-}
-
-void NetworkTimeTracker::SetMaxResponseSizeForTesting(size_t limit) {
-  max_response_size_ = limit;
-}
-
-void NetworkTimeTracker::SetPublicKeyForTesting(const base::StringPiece& key) {
-  query_signer_ = client_update_protocol::Ecdsa::Create(kKeyVersion, key);
-}
-
-bool NetworkTimeTracker::QueryTimeServiceForTesting() {
-  QueryTimeService();
-  loop_ = base::MessageLoop::current();  // Gets Quit on completion.
-  return time_fetcher_ != nullptr;
-}
-
-void NetworkTimeTracker::WaitForFetchForTesting(uint32_t nonce) {
-  query_signer_->OverrideNonceForTesting(kKeyVersion, nonce);
-  base::MessageLoop::current()->Run();
-}
-
-base::TimeDelta NetworkTimeTracker::GetTimerDelayForTesting() const {
-  DCHECK(query_timer_.IsRunning());
-  return query_timer_.GetCurrentDelay();
 }
 
 bool NetworkTimeTracker::GetNetworkTime(base::Time* network_time,
@@ -281,117 +167,4 @@
   return true;
 }
 
-void NetworkTimeTracker::QueryTimeService() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  // Do not query the time service if not enabled via Finch.
-  if (!base::FeatureList::IsEnabled(kNetworkTimeServiceQuerying)) {
-    return;
-  }
-
-  // If GetNetworkTime() returns true, the NetworkTimeTracker thinks it is in
-  // sync, so there is no need to query.
-  base::Time network_time;
-  if (GetNetworkTime(&network_time, nullptr)) {
-    return;
-  }
-
-  std::string query_string;
-  query_signer_->SignRequest(nullptr, &query_string);
-  GURL url = server_url_;
-  GURL::Replacements replacements;
-  replacements.SetQueryStr(query_string);
-  url = url.ReplaceComponents(replacements);
-
-  // This cancels any outstanding fetch.
-  time_fetcher_ = net::URLFetcher::Create(url, net::URLFetcher::GET, this);
-  if (!time_fetcher_) {
-    DVLOG(1) << "tried to make fetch happen; failed";
-    return;
-  }
-  time_fetcher_->SaveResponseWithWriter(
-      std::unique_ptr<net::URLFetcherResponseWriter>(
-          new SizeLimitingStringWriter(max_response_size_)));
-  DCHECK(getter_);
-  time_fetcher_->SetRequestContext(getter_.get());
-  // Not expecting any cookies, but just in case.
-  time_fetcher_->SetLoadFlags(net::LOAD_BYPASS_CACHE | net::LOAD_DISABLE_CACHE |
-                              net::LOAD_DO_NOT_SAVE_COOKIES |
-                              net::LOAD_DO_NOT_SEND_COOKIES |
-                              net::LOAD_DO_NOT_SEND_AUTH_DATA);
-  time_fetcher_->Start();
-  fetch_started_ = tick_clock_->NowTicks();
-}
-
-bool NetworkTimeTracker::UpdateTimeFromResponse() {
-  if (time_fetcher_->GetStatus().status() != net::URLRequestStatus::SUCCESS &&
-      time_fetcher_->GetResponseCode() != 200) {
-    DVLOG(1) << "fetch failed, status=" << time_fetcher_->GetStatus().status()
-             << ",code=" << time_fetcher_->GetResponseCode();
-    return false;
-  }
-
-  std::string response_body;
-  if (!time_fetcher_->GetResponseAsString(&response_body)) {
-    DVLOG(1) << "failed to get response";
-    return false;
-  }
-  DCHECK(query_signer_);
-  if (!query_signer_->ValidateResponse(response_body,
-                                       GetServerProof(time_fetcher_.get()))) {
-    DVLOG(1) << "invalid signature";
-    return false;
-  }
-  response_body = response_body.substr(5);  // Skips leading )]}'\n
-  std::unique_ptr<base::Value> value = base::JSONReader::Read(response_body);
-  if (!value) {
-    DVLOG(1) << "bad JSON";
-    return false;
-  }
-  const base::DictionaryValue* dict;
-  if (!value->GetAsDictionary(&dict)) {
-    DVLOG(1) << "not a dictionary";
-    return false;
-  }
-  double current_time_millis;
-  if (!dict->GetDouble("current_time_millis", &current_time_millis)) {
-    DVLOG(1) << "no current_time_millis";
-    return false;
-  }
-  // There is a "server_nonce" key here too, but it serves no purpose other than
-  // to make the server's response unpredictable.
-  base::Time current_time = base::Time::FromJsTime(current_time_millis);
-  base::TimeDelta resolution =
-      base::TimeDelta::FromMilliseconds(1) +
-      base::TimeDelta::FromSeconds(kTimeServerMaxSkewSeconds);
-  base::TimeDelta latency = tick_clock_->NowTicks() - fetch_started_;
-  UpdateNetworkTime(current_time, resolution, latency, tick_clock_->NowTicks());
-  return true;
-}
-
-void NetworkTimeTracker::OnURLFetchComplete(const net::URLFetcher* source) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(time_fetcher_);
-  DCHECK_EQ(source, time_fetcher_.get());
-
-  if (!UpdateTimeFromResponse()) {  // On error, back off.
-    DCHECK(query_timer_.IsRunning());
-    base::TimeDelta delay = query_timer_.GetCurrentDelay();
-    if (delay < base::TimeDelta::FromDays(2)) {
-      delay *= 2;
-    }
-    QueueTimeQuery(delay);
-  }
-  time_fetcher_.reset();
-  if (loop_ != nullptr) {
-    loop_->QuitWhenIdle();
-    loop_ = nullptr;
-  }
-}
-
-void NetworkTimeTracker::QueueTimeQuery(base::TimeDelta delay) {
-  query_timer_.Start(FROM_HERE, delay, this,
-                     &NetworkTimeTracker::QueryTimeService);
-}
-
 }  // namespace network_time