[Policy] HostContentSettingsMap: Add AreUserExceptionsAllowedForType() and tests.

components/content_settings/core/browser/host_content_settings_map.h

Index: components/content_settings/core/browser/host_content_settings_map.h
diff --git a/components/content_settings/core/browser/host_content_settings_map.h b/components/content_settings/core/browser/host_content_settings_map.h
index 7a75222a41f073a10c60b6e62f2b4280e7fc4cc1..f385b004b34e669a883e5182c23e571af7d99f83 100644
--- a/components/content_settings/core/browser/host_content_settings_map.h
+++ b/components/content_settings/core/browser/host_content_settings_map.h
@@ -36,6 +36,7 @@ class Value;
 
 namespace content_settings {
 class ObservableProvider;
+class PolicyProvider;
 class ProviderInterface;
 class PrefProvider;
 class TestUtils;
@@ -58,7 +59,12 @@ class HostContentSettingsMap : public content_settings::Observer,
     CUSTOM_EXTENSION_PROVIDER,
     PREF_PROVIDER,
     DEFAULT_PROVIDER,
-    NUM_PROVIDER_TYPES,
+    NUM_PROVIDER_TYPES
+  };
+
+  struct ContentSettingWithProviderType {
+    ContentSetting content_setting = CONTENT_SETTING_DEFAULT;
+    ProviderType provider_type = NUM_PROVIDER_TYPES;
   };
 
   // This should be called on the UI thread, otherwise |thread_checker_| handles
@@ -75,13 +81,18 @@ class HostContentSettingsMap : public content_settings::Observer,
       ProviderType type,
       scoped_ptr<content_settings::ObservableProvider> provider);
 
-  // Returns the default setting for a particular content type. If |provider_id|
-  // is not NULL, the id of the provider which provided the default setting is
-  // assigned to it.
+  // Returns the default setting and the provider type for a given content type.
+  //
+  // This may be called on any thread.
+  ContentSettingWithProviderType
+      GetDefaultContentSetting(ContentSettingsType content_type) const;

[raymes, 2016/04/12 04:52:47]

I don't think we should have two functions for GetDefaultContentSetting. It adds
complexity to the interface and we're currently in the process of trying to make
the interface more simple :). I would suggest either 1) refactoring all the
callsites to use the new interface (in a separate CL) or 2) just use the old
version of GetDefaultContentSetting and compare the string returned to "policy".

If you don't want to do 1) we could just do 2) for now and come back and
refactoring later. Would that work?

[huangs, 2016/04/12 14:19:14]

I'm fine with changing all callers (see FIXME(huangs) in the .cc file), but that
will bloat this CL.  Probably better to omit this from this CL and do all this
in a separate CL, with callers and all.

[huangs, 2016/04/13 17:36:18]

Removed from this CL.

+
+  // Alternative interface that returns the content setting, and writes the
+  // provider name to |provider_name| if not null.
   //
   // This may be called on any thread.
   ContentSetting GetDefaultContentSetting(ContentSettingsType content_type,
-                                          std::string* provider_id) const;
+                                          std::string* provider_name) const;
 
   // Returns a single |ContentSetting| which applies to the given URLs.  Note
   // that certain internal schemes are whitelisted. For |CONTENT_TYPE_COOKIES|,
@@ -131,6 +142,10 @@ class HostContentSettingsMap : public content_settings::Observer,
   void SetDefaultContentSetting(ContentSettingsType content_type,
                                 ContentSetting setting);
 
+  // Returns whether user preference exceptions may be enabled for a given
+  // content type.
+  bool AreUserExceptionsAllowedForType(ContentSettingsType content_type) const;
+
   // Sets the content |setting| for the given patterns, |content_type| and
   // |resource_identifier|. Setting the value to CONTENT_SETTING_DEFAULT causes
   // the default setting for that type to be used when loading pages matching
@@ -373,6 +388,12 @@ class HostContentSettingsMap : public content_settings::Observer,
   // before any other uses of it.
   ProviderMap content_settings_providers_;
 
+  // content_settings_providers_[POLICY_PROVIDER] but specialized.
+  content_settings::PolicyProvider* policy_provider_ = nullptr;
+
+  // content_settings_providers_[PREF_PROVIDER] but specialized.
+  content_settings::PrefProvider* pref_provider_ = nullptr;
+
   base::ThreadChecker thread_checker_;
 
   base::ObserverList<content_settings::Observer> observers_;