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

chrome/common/pref_names.h

Index: chrome/common/pref_names.h
diff --git a/chrome/common/pref_names.h b/chrome/common/pref_names.h
index 86ba49aa1d442f30d24ab27f31aebdd2d7b0c34c..e63e0d510de265704bd0b4027d2e720dc7657284 100644
--- a/chrome/common/pref_names.h
+++ b/chrome/common/pref_names.h
@@ -169,13 +169,11 @@ extern const char kPromptForDownload[];
 extern const char kAlternateErrorPagesEnabled[];
 extern const char kDnsPrefetchingStartupList[];
 extern const char kDnsPrefetchingHostReferralList[];
-extern const char kDisableSpdy[];
 extern const char kHttpServerProperties[];
 #if defined(OS_ANDROID)
 extern const char kLastPolicyCheckTime[];
 #endif
 extern const char kInstantUIZeroSuggestUrlPrefix[];
-extern const char kNetworkPredictionEnabled[];
 extern const char kNetworkPredictionOptions[];
 extern const char kDefaultAppsInstallState[];
 extern const char kHideWebStoreIcon[];