Remove NetPrefObserver class and two prefs that do not do anything.

chrome/common/pref_names.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.
 
 #include "chrome/common/pref_names.h"
 
 #include "base/macros.h"
 #include "build/build_config.h"
 #include "chrome/common/pref_font_webkit_names.h"
 
@@ skipping 415 matching lines @@
 // next startup, based on what was actually needed during this startup.
 const char kDnsPrefetchingStartupList[] = "dns_prefetching.startup_list";
 
 // A list of host names used to fetch web pages, and their commonly used
 // sub-resource hostnames (and expected latency benefits from pre-resolving, or
 // preconnecting to, such sub-resource hostnames).
 // This list is adaptively grown and pruned.
 const char kDnsPrefetchingHostReferralList[] =
     "dns_prefetching.host_referral_list";
 
-// Disables the SPDY/3.1 protocol.
-// DEPRECATED: SPDY/3.1 is not supported any more.
-const char kDisableSpdy[] = "spdy.disabled";
-
 // Prefs for persisting HttpServerProperties.
 const char kHttpServerProperties[] = "net.http_server_properties";
 
 #if defined(OS_ANDROID)
 // Last time that a check for cloud policy management was done. This time is
 // recorded on Android so that retries aren't attempted on every startup.
 // Instead the cloud policy registration is retried at least 1 or 3 days later.
 const char kLastPolicyCheckTime[] = "policy.last_policy_check_time";
 #endif
 
 // Prefix URL for the experimental Instant ZeroSuggest provider.
 const char kInstantUIZeroSuggestUrlPrefix[] =
     "instant_ui.zero_suggest_url_prefix";
 
-// A boolean pref set to true if prediction of network actions is allowed.
-// Actions include DNS prefetching, TCP and SSL preconnection, prerendering
-// of web pages, and resource prefetching.
-// NOTE: The "dns_prefetching.enabled" value is used so that historical user
-// preferences are not lost.
-// TODO(bnc): Remove kNetworkPredictionEnabled once kNetworkPredictionOptions
-// is functioning as per crbug.com/334602.

[gab, 2016/07/22 16:44:33]

Should crbug.com/334602 be listed in CL description?

[Bence, 2016/07/23 00:16:42]

Done.

-const char kNetworkPredictionEnabled[] = "dns_prefetching.enabled";
-
 // A preference of enum chrome_browser_net::NetworkPredictionOptions shows
 // if prediction of network actions is allowed, depending on network type.
 // Actions include DNS prefetching, TCP and SSL preconnection, prerendering
 // of web pages, and resource prefetching.
 // TODO(bnc): Implement this preference as per crbug.com/334602.
 const char kNetworkPredictionOptions[] = "net.network_prediction_options";
 
 // An integer representing the state of the default apps installation process.
 // This value is persisted in the profile's user preferences because the process
 // is async, and the user may have stopped chrome in the middle.  The next time
@@ skipping 1775 matching lines @@
 #endif
 
 // The base64-encoded representation of the public key to use to validate origin
 // trial token signatures.
 const char kOriginTrialPublicKey[] = "origin_trials.public_key";
 
 // A list of origin trial features to disable by policy.
 const char kOriginTrialDisabledFeatures[] = "origin_trials.disabled_features";
 
 }  // namespace prefs