[Offline pages] Add a builder and feature struct to policy

components/offline_pages/offline_page_client_policy.h

Index: components/offline_pages/offline_page_client_policy.h
diff --git a/components/offline_pages/offline_page_client_policy.h b/components/offline_pages/offline_page_client_policy.h
index de7ae526b0038685b403773c3a2ec1bcd3c14aa0..714a402d6b27568c1feb6fb04654ed27ee34d282 100644
--- a/components/offline_pages/offline_page_client_policy.h
+++ b/components/offline_pages/offline_page_client_policy.h
@@ -32,13 +32,21 @@ struct LifetimePolicy {
   LifetimeType lifetime_type;

[dewittj, 2016/09/12 21:40:53]

I might also assign defaults here and in page_limit, just so that it's obvious.

Are you trying to keep this POD?  If not then it might be useful to just define
a constructor or two for these data types.

[chili, 2016/09/13 00:36:10]

Done.

 
   // The time after which the page expires.
-  base::TimeDelta expiration_period;
+  base::TimeDelta expiration_period = base::TimeDelta::FromDays(0);
 
   // The maximum number of pages allowed to be saved by the namespace.
   // kUnlimitedPages (defined above) means no limit set.
   size_t page_limit;
 };
 
+// The struct describing feature set of the offline pages.
+struct FeaturePolicy {
+  // Whether pages are shown in download ui.
+  bool is_supported_by_download = false;
+  // Whether pages are removed on user-initiated cache reset. Defaults to true.
+  bool is_removed_on_cache_reset = true;
+};
+
 // The struct describing policies for various namespaces (Bookmark, Last-N etc.)
 // used by offline page model. The name_space is supposed to be key, so that
 // it's sufficient to compare name_space only when doing comparisons.
@@ -52,6 +60,50 @@ struct OfflinePageClientPolicy {
   // How many pages for the same online URL can be stored at any time.
   // kUnlimitedPages means there's no limit.
   size_t pages_allowed_per_url;
+
+  FeaturePolicy feature_policy;
+};
+
+class OfflinePageClientPolicyBuilder {
+ public:
+  OfflinePageClientPolicyBuilder(const std::string& name_space,
+                                 LifetimePolicy::LifetimeType lifetime_type,
+                                 size_t page_limit,
+                                 size_t pages_allowed_per_url) {
+    policy_ = OfflinePageClientPolicy();

[dewittj, 2016/09/12 21:40:53]

Is this line strictly necessary?  I think it should already be a default policy
object since it's not in the member initializer list

[chili, 2016/09/13 00:36:10]

Done.

+    policy_.name_space = name_space;
+    policy_.lifetime_policy.lifetime_type = lifetime_type;
+    policy_.lifetime_policy.page_limit = page_limit;
+    policy_.pages_allowed_per_url = pages_allowed_per_url;
+  }
+
+  ~OfflinePageClientPolicyBuilder() {}
+
+  // Calling build does not reset the object inside.
+  const OfflinePageClientPolicy Build() const { return policy_; }
+
+  OfflinePageClientPolicyBuilder& SetExpirePeriod(
+      const base::TimeDelta& expire_period) {
+    policy_.lifetime_policy.expiration_period = expire_period;
+    return *this;
+  }
+
+  OfflinePageClientPolicyBuilder& SetIsSupportedByDownload(
+      const bool is_downloaded) {
+    policy_.feature_policy.is_supported_by_download = is_downloaded;
+    return *this;
+  }
+
+  OfflinePageClientPolicyBuilder& SetIsRemovedOnCacheReset(
+      const bool removed_on_cache_reset) {
+    policy_.feature_policy.is_removed_on_cache_reset = removed_on_cache_reset;
+    return *this;
+  }
+
+ private:
+  OfflinePageClientPolicy policy_;
+
+  DISALLOW_COPY_AND_ASSIGN(OfflinePageClientPolicyBuilder);
 };
 
 }  // namespace offline_pages