Add support for multiple simultaneous subresource_filter::Configurations.

components/subresource_filter/core/browser/subresource_filter_features.h

Index: components/subresource_filter/core/browser/subresource_filter_features.h
diff --git a/components/subresource_filter/core/browser/subresource_filter_features.h b/components/subresource_filter/core/browser/subresource_filter_features.h
index c6106319cac4c7ab993d0b3b08c1a29f86f65257..e075356c3c22d1ee67528b60f1d3e86020025b51 100644
--- a/components/subresource_filter/core/browser/subresource_filter_features.h
+++ b/components/subresource_filter/core/browser/subresource_filter_features.h
@@ -5,72 +5,145 @@
 #ifndef COMPONENTS_SUBRESOURCE_FILTER_CORE_BROWSER_SUBRESOURCE_FILTER_FEATURES_H_
 #define COMPONENTS_SUBRESOURCE_FILTER_CORE_BROWSER_SUBRESOURCE_FILTER_FEATURES_H_
 
+#include <iosfwd>
+#include <vector>
+
 #include "base/feature_list.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "base/strings/string_piece.h"
 #include "components/subresource_filter/core/common/activation_level.h"
 #include "components/subresource_filter/core/common/activation_list.h"
 #include "components/subresource_filter/core/common/activation_scope.h"
 
 namespace subresource_filter {
 
-// Encapsulates all parameters that define how the subresource filter feature
-// should operate.
+// Encapsulates a set of parameters that define how the subresource filter
+// feature should operate. Each configuration consists of three parts as
+// described in detail below.
+//
+// There can be multiple configuration enabled at the same time. For each
+// navigation, however, subresource filtering will be activated according to
+// exactly one of these enabled configuration, if any. Namely, the configuration
+// with the highest |priority| among those whose |activation_conditions| are
+// otherwise satisfied for the navigation.
+//
+// Even when there are multiple enabled configurations, the RulesetService is
+// currently only capable of fetching and indexing a single |ruleset_flavor|,
+// which will be used for all navigations with subresource filtering activated,
+// regardless of which configuration prescribed filtering for that navigation.
+// This shared ruleset flavor will be the one lexicographically greatest.
+//
+// Experimenters wishing to use customized rulesets therefore must ensure that
+// they set up the experimental state so that the ruleset chosen through this
+// mechanism is compatible with all the enabled configurations (or disable some
+// as needed).
 struct Configuration {
+  // The conditions that determine whether subresource filtering should be
+  // activated for a given main frame navigation using this configuration.
+  struct ActivationConditions {
+    // The activation scope. That is, the subset of page loads where subresource
+    // filtering should be activated according to this configuration. When set
+    // to NO_SITES, this configuration will never be active.
+    ActivationScope activation_scope = ActivationScope::NO_SITES;
+
+    // The activation list to use when the |activation_scope| is
+    // ACTIVATION_LIST, ignored otherwise.
+    ActivationList activation_list = ActivationList::NONE;
+
+    // The activation priority of this configuration. Used to break ties when
+    // there are multiple configurations whose activation conditions are
+    // otherwise satisfied. A greater value indicates higher priority.
+    int priority = 0;
+  };
+
+  // The details of how subresource filtering should operate for a given main
+  // frame navigation when it is activated using this configuration.
+  struct ActivationOptions {
+    // The maximum degree to which subresource filtering should be activated on
+    // any RenderFrame. When set to DISABLED, this configuration will cause
+    // subresource filtering to be de-activated for a navigation if this is the
+    // highest priority configuration with its activation conditions met.
+    ActivationLevel activation_level = ActivationLevel::DISABLED;
+
+    // A number in the range [0, 1], indicating the fraction of page loads that
+    // should have extended performance measurements enabled.
+    double performance_measurement_rate = 0.0;
+
+    // Whether notifications indicating that a subresource was disallowed should
+    // be suppressed in the UI.
+    bool should_suppress_notifications = false;
+
+    // Whether to whitelist a site when a page loaded from that site is
+    // reloaded.
+    bool should_whitelist_site_on_reload = false;
+  };
+
+  // General settings that apply outside of the scope of a navigation.
+  struct GeneralSettings {
+    // The ruleset flavor to download through the component updater. The empty
+    // string indicates that the default ruleset should be used.
+    std::string ruleset_flavor;
+  };
+
+  // Do not forget updating operator==, operator<<, and any other necessary
+  // methods when adding new fields here!
+
   Configuration();
   Configuration(ActivationLevel activation_level,
                 ActivationScope activation_scope,
                 ActivationList activation_list = ActivationList::NONE);
+  Configuration(const Configuration&);
   Configuration(Configuration&&);
   ~Configuration();
+  Configuration& operator=(const Configuration&);
   Configuration& operator=(Configuration&&);
 
-  // The maximum degree to which subresource filtering should be activated on
-  // any RenderFrame. This will be ActivationLevel::DISABLED unless the feature
-  // is enabled and variation parameters prescribe a higher activation level.
-  ActivationLevel activation_level = ActivationLevel::DISABLED;
-
-  // The activation scope. That is, the subset of page loads where subresource
-  // filtering should be activated. This will be ActivationScope::NO_SITES
-  // unless the feature is =enabled and variation parameters prescribe a wider
-  // activation scope.
-  ActivationScope activation_scope = ActivationScope::NO_SITES;
-
-  // The activation list to use when the |activation_scope| is ACTIVATION_LIST.
-  // This will be ActivationList::NONE unless variation parameters prescribe a
-  // recognized list.
-  ActivationList activation_list = ActivationList::NONE;
-
-  // A number in the range [0, 1], indicating the fraction of page loads that
-  // should have extended performance measurements enabled. The rate will
-  // be 0 unless a greater frequency is specified by variation parameters.
-  double performance_measurement_rate = 0.0;
-
-  // Whether notifications indicating that a subresource was disallowed should
-  // be suppressed in the UI.
-  bool should_suppress_notifications = false;
-
-  // The ruleset flavor to download through the component updater. This or the
-  // empty string if the default ruleset should be used.
-  std::string ruleset_flavor;
-
-  // Whether to whitelist a site when a page loaded from that site is reloaded.
-  bool should_whitelist_site_on_reload = false;
+  bool operator==(const Configuration& rhs) const;
+  bool operator!=(const Configuration& rhs) const;
+
+  // Factory methods for preset configurations.
+  //
+  // To add a new preset:
+  //  1.) Define a named factory method here.
+  //  2.) Define a name for the configuration to be used in variation params.
+  //  3.) Register it into |kAvailablePresetConfigurations| in the .cc file.
+  //  4.) Update unittests to cover the new preset.
+  static Configuration MakePresetForLiveRunOnPhishingSites();
+  static Configuration MakePresetForPerformanceTestingDryRunOnAllSites();
+
+  ActivationConditions activation_conditions;
+  ActivationOptions activation_options;
+  GeneralSettings general_settings;
 };
 
-// TODO(engedy): Make this an actual list once all call sites are prepared to
-// handle multiple simultaneous configurations.
+// For logging in tests.
+std::ostream& operator<<(std::ostream& os, const Configuration& config);
+
+// Thread-safe, ref-counted wrapper around an immutable list of configurations.
 class ConfigurationList : public base::RefCountedThreadSafe<ConfigurationList> {
  public:
-  explicit ConfigurationList(Configuration config);
+  explicit ConfigurationList(std::vector<Configuration> configs);
 
-  const Configuration& the_one_and_only() const { return config_; }
+  // Returns the lexicographically greatest flavor string that is prescribed by
+  // any of the configurations. The caller must hold a reference to this
+  // instance while using the returned string piece.
+  base::StringPiece lexicographically_greatest_ruleset_flavor() const {
+    return lexicographically_greatest_ruleset_flavor_;
+  }
+
+  // Retrieves the configurations pre-sorted in decreasing order of their
+  // |activation_condition.priority|.
+  const std::vector<Configuration>& configs_by_decreasing_priority() const {
+    return configs_by_decreasing_priority_;
+  }
 
  private:
   friend class base::RefCountedThreadSafe<ConfigurationList>;
   ~ConfigurationList();
 
-  const Configuration config_;
+  const std::vector<Configuration> configs_by_decreasing_priority_;
+  const base::StringPiece lexicographically_greatest_ruleset_flavor_;
 
   DISALLOW_COPY_AND_ASSIGN(ConfigurationList);
 };
@@ -78,13 +151,13 @@ class ConfigurationList : public base::RefCountedThreadSafe<ConfigurationList> {
 // Retrieves all currently enabled subresource filtering configurations. The
 // configurations are parsed on first access and then the result is cached.
 //
-// In tests, however, the config may be altered in-between navigations, so
+// In tests, however, the config may be changed in-between navigations, so
 // callers should not hold on to the result for long.
-scoped_refptr<ConfigurationList> GetActiveConfigurations();
+scoped_refptr<ConfigurationList> GetEnabledConfigurations();
 
 namespace testing {
 
-// Returns the currently cached active ConfigurationList, if any, and replaces
+// Returns the currently cached enabled ConfigurationList, if any, and replaces
 // it with |new_configs|, which may be nullptr to clear the cache.
 scoped_refptr<ConfigurationList> GetAndSetActivateConfigurations(
     scoped_refptr<ConfigurationList> new_configs);
@@ -115,7 +188,7 @@ extern const char kActivationListSocialEngineeringAdsInterstitial[];
 extern const char kActivationListPhishingInterstitial[];
 extern const char kActivationListSubresourceFilter[];
 
-extern const char kRulesetFlavorParameterName[];
+extern const char kActivationPriorityParameterName[];
 
 extern const char kPerformanceMeasurementRateParameterName[];
 
@@ -123,6 +196,13 @@ extern const char kSuppressNotificationsParameterName[];
 
 extern const char kWhitelistSiteOnReloadParameterName[];
 
+extern const char kRulesetFlavorParameterName[];
+
+extern const char kEnablePresetsParameterName[];
+extern const char kDisablePresetsParameterName[];
+extern const char kPresetLiveRunOnPhishingSites[];
+extern const char kPresetPerformanceTestingDryRunOnAllSites[];
+
 }  // namespace subresource_filter
 
 #endif  // COMPONENTS_SUBRESOURCE_FILTER_CORE_BROWSER_SUBRESOURCE_FILTER_FEATURES_H_