Introduce subresource_filter::Configuration.

components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc

Index: components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc
diff --git a/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc b/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc
index 97f23d1ab8fb7b4476f417638f42d31d412578d5..cb0c6d2b41155b4e1b9596fd8d88c658a2739c57 100644
--- a/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc
+++ b/components/subresource_filter/content/browser/content_subresource_filter_driver_factory.cc
@@ -34,14 +34,14 @@ std::string DistillURLToHostAndPath(const GURL& url) {
   return url.host() + url.path();
 }
 
-// Returns true with a probability of GetPerformanceMeasurementRate() if
-// ThreadTicks is supported, otherwise returns false.
-bool ShouldMeasurePerformanceForPageLoad() {
+// Returns true with a probability given by |performance_measurement_rate| in
+// |configuration| if ThreadTicks is supported, otherwise returns false.
+bool ShouldMeasurePerformanceForPageLoad(const Configuration& configuration) {
   if (!base::ThreadTicks::IsSupported())
     return false;
   // TODO(pkalinnikov): Cache |rate| and other variation params in
   // ContentSubresourceFilterDriverFactory.
-  const double rate = GetPerformanceMeasurementRate();
+  const double rate = configuration.performance_measurement_rate;
   return rate == 1 || (rate > 0 && base::RandDouble() < rate);
 }
 
@@ -146,11 +146,10 @@ void ContentSubresourceFilterDriverFactory::AddHostOfURLToWhitelistSet(
 ContentSubresourceFilterDriverFactory::ActivationDecision
 ContentSubresourceFilterDriverFactory::ComputeActivationDecisionForMainFrameURL(
     const GURL& url) const {
-  if (GetMaximumActivationLevel() == ActivationLevel::DISABLED)
+  if (configuration_.activation_level == ActivationLevel::DISABLED)
     return ActivationDecision::ACTIVATION_DISABLED;
 
-  ActivationScope scope = GetCurrentActivationScope();
-  if (scope == ActivationScope::NO_SITES)
+  if (configuration_.activation_scope == ActivationScope::NO_SITES)
     return ActivationDecision::ACTIVATION_DISABLED;
 
   if (!url.SchemeIsHTTPOrHTTPS())
@@ -158,7 +157,7 @@ ContentSubresourceFilterDriverFactory::ComputeActivationDecisionForMainFrameURL(
   if (IsWhitelisted(url))
     return ActivationDecision::URL_WHITELISTED;
 
-  switch (scope) {
+  switch (configuration_.activation_scope) {
     case ActivationScope::ALL_SITES:
       return ActivationDecision::ACTIVATED;
     case ActivationScope::ACTIVATION_LIST: {
@@ -166,10 +165,11 @@ ContentSubresourceFilterDriverFactory::ComputeActivationDecisionForMainFrameURL(
       // AddActivationListMatch to ensure the activation list only has relevant
       // entries.
       DCHECK(url.SchemeIsHTTPOrHTTPS() ||
-             !DidURLMatchActivationList(url, GetCurrentActivationList()));
+             !DidURLMatchActivationList(url, configuration_.activation_list));
       bool should_activate =
-          DidURLMatchActivationList(url, GetCurrentActivationList());
-      if (GetCurrentActivationList() == ActivationList::PHISHING_INTERSTITIAL) {
+          DidURLMatchActivationList(url, configuration_.activation_list);
+      if (configuration_.activation_list ==
+          ActivationList::PHISHING_INTERSTITIAL) {
         // Handling special case, where activation on the phishing sites also
         // mean the activation on the sites with social engineering metadata.
         should_activate |= DidURLMatchActivationList(
@@ -213,7 +213,7 @@ void ContentSubresourceFilterDriverFactory::WillProcessResponse(
 
   RecordRedirectChainMatchPattern();
 
-  if (ShouldWhitelistSiteOnReload() &&
+  if (configuration_.should_whitelist_site_on_reload &&
       NavigationIsPageReload(url, referrer, transition)) {
     // Whitelist this host for the current as well as subsequent navigations.
     AddHostOfURLToWhitelistSet(url);
@@ -226,16 +226,16 @@ void ContentSubresourceFilterDriverFactory::WillProcessResponse(
     return;
   }
 
-  activation_level_ = GetMaximumActivationLevel();
+  activation_level_ = configuration_.activation_level;
   measure_performance_ = activation_level_ != ActivationLevel::DISABLED &&
-                         ShouldMeasurePerformanceForPageLoad();
+                         ShouldMeasurePerformanceForPageLoad(configuration_);
   ActivationState state = ActivationState(activation_level_);
   state.measure_performance = measure_performance_;
   throttle_manager_->NotifyPageActivationComputed(navigation_handle, state);
 }
 
 void ContentSubresourceFilterDriverFactory::OnFirstSubresourceLoadDisallowed() {
-  if (ShouldSuppressNotifications())
+  if (configuration_.should_suppress_notifications)
     return;
 
   client_->ToggleNotificationVisibility(activation_level_ ==
@@ -261,6 +261,10 @@ void ContentSubresourceFilterDriverFactory::DidStartNavigation(
     content::NavigationHandle* navigation_handle) {
   if (navigation_handle->IsInMainFrame() &&
       !navigation_handle->IsSameDocument()) {
+    // TODO(https://crbug.com/708181): Somewhat hacky workaround to allow tests
+    // to change the configuration after construction. Can be removed once the
+    // Safe Browsing navigation throttle handles all activation decisions.
+    configuration_ = GetActiveConfiguration();

[Charlie Harrison, 2017/04/05 20:43:04]

Eek this scares me, especially if code accidentally gets added in the meantime
that uses configuration_ before DidStartNavigation.

What about keeping this as a unique_ptr and exposing a
set_configuration_for_testing()?  It means more code to cleanup, unfortunately.

I would also be okay with using base::Optional, so that we get DCHECks around
picking configuration_.value().

[engedy, 2017/04/07 08:40:58]

Much relieved. I was worried that it might not scare you and if I pick one of
these more verbose alternatives, I might get accused of over-engineering things.
:-)

How about this?

     activation_decision_ = ActivationDecision::UNKNOWN;
     ResetActivationState();
     navigation_chain_.push_back(navigation_handle->GetURL());