Check if precaching is allowed for the current browser context before

measuring any precache-related metrics.

BUG=309216

Review URL: https://codereview.chromium.org/514353002

Cr-Commit-Position: refs/heads/master@{#292677}

chrome/browser/net/chrome_network_delegate.cc

@@ -217,8 +217,8 @@ void RecordPrecacheStatsOnUIThread(const GURL& url,
 
   precache::PrecacheManager* precache_manager =
       precache::PrecacheManagerFactory::GetForBrowserContext(profile);
-  if (!precache_manager) {
-    // This could be NULL if the profile is off the record.
+  if (!precache_manager || !precache_manager->IsPrecachingAllowed()) {
+    // |precache_manager| could be NULL if the profile is off the record.
     return;
   }
 

components/precache/content/DEPS

 include_rules = [
+  "+components/data_reduction_proxy/common",
   "+components/keyed_service",
+  "+components/user_prefs",
   "+content/public/browser",
   "+net/base",
 ]

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) {

components/precache/content/precache_manager.h

@@ -49,6 +49,9 @@ class PrecacheManager : public KeyedService,
   // command line flag. This method can be called on any thread.
   static bool IsPrecachingEnabled();
 
+  // Returns true if precaching is allowed for the browser context.
+  bool IsPrecachingAllowed();
+
   // Starts precaching resources that the user is predicted to fetch in the
   // future. If precaching is already currently in progress, then this method
   // does nothing. The |precache_completion_callback| will be run when