Check if precaching is allowed before reporting related metrics

components/precache/content/precache_manager.cc

Index: components/precache/content/precache_manager.cc
diff --git a/components/precache/content/precache_manager.cc b/components/precache/content/precache_manager.cc
index 2998eb142621a41b4f434a49360edad6c7798201..f222163d7c94ec2fc488bfc2c4b1c0c88d2465f2 100644
--- a/components/precache/content/precache_manager.cc
+++ b/components/precache/content/precache_manager.cc
@@ -9,10 +9,13 @@
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
+#include "base/prefs/pref_service.h"
 #include "base/time/time.h"
+#include "components/data_reduction_proxy/common/data_reduction_proxy_pref_names.h"
 #include "components/precache/core/precache_database.h"
 #include "components/precache/core/precache_switches.h"
 #include "components/precache/core/url_list_provider.h"
+#include "components/user_prefs/user_prefs.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/browser_thread.h"
 #include "net/base/network_change_notifier.h"
@@ -50,6 +53,16 @@ bool PrecacheManager::IsPrecachingEnabled() {
          CommandLine::ForCurrentProcess()->HasSwitch(switches::kEnablePrecache);
 }
 
+bool PrecacheManager::IsPrecachingAllowed() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+#if defined(SPDY_PROXY_AUTH_ORIGIN)
+  return user_prefs::UserPrefs::Get(browser_context_)->GetBoolean(
+      data_reduction_proxy::prefs::kDataReductionProxyEnabled);
+#else
+  return false;
+#endif
+}
+
 void PrecacheManager::StartPrecaching(
     const PrecacheCompletionCallback& precache_completion_callback,
     URLListProvider* url_list_provider) {