[Patch 3 of 6] Split out content/child's SiteIsolationPolicy into two new classes.

content/child/site_isolation_policy.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_SITE_ISOLATION_POLICY_H_
 #define CONTENT_CHILD_SITE_ISOLATION_POLICY_H_
 
 #include <map>
 #include <utility>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/linked_ptr.h"
 #include "base/strings/string_piece.h"
 #include "content/common/content_export.h"
 #include "content/public/common/resource_type.h"
 #include "url/gurl.h"
 
 namespace content {
 
 struct ResourceResponseInfo;
 
-// SiteIsolationPolicy implements the cross-site document blocking policy (XSDP)
-// for Site Isolation. XSDP will monitor network responses to a renderer and
-// block illegal responses so that a compromised renderer cannot steal private
-// information from other sites. For now SiteIsolationPolicy monitors responses
-// to gather various UMA stats to see the compatibility impact of actual
-// deployment of the policy. The UMA stat categories SiteIsolationPolicy gathers
-// are as follows:
+// CrossSiteDocumentClassifier implements the cross-site document blocking
+// policy (XSDP) for Site Isolation. XSDP will monitor network responses to a
+// renderer and block illegal responses so that a compromised renderer cannot
+// steal private information from other sites.
+//
+// SiteIsolationStatsGatherer monitors responses to gather various UMA stats to
+// see the compatibility impact of actual deployment of the policy. The UMA stat
+// categories SiteIsolationStatsGatherer gathers are as follows:
 //
 // SiteIsolation.AllResponses : # of all network responses.
 // SiteIsolation.XSD.DataLength : the length of the first packet of a response.
 // SiteIsolation.XSD.MimeType (enum):
 //   # of responses from other sites, tagged with a document mime type.
 //   0:HTML, 1:XML, 2:JSON, 3:Plain, 4:Others
 // SiteIsolation.XSD.[%MIMETYPE].Blocked :
 //   blocked # of cross-site document responses grouped by sniffed MIME type.
 // SiteIsolation.XSD.[%MIMETYPE].Blocked.RenderableStatusCode :
 //   # of responses with renderable status code,
@@ skipping 27 matching lines @@
   SiteIsolationResponseMetaData();
 
   std::string frame_origin;
   GURL response_url;
   ResourceType resource_type;
   CanonicalMimeType canonical_mime_type;
   int http_status_code;
   bool no_sniff;
 };
 
-class CONTENT_EXPORT SiteIsolationPolicy {
+// TODO(nick): Move this class into its own file.
+class CONTENT_EXPORT SiteIsolationStatsGatherer {
  public:
   // Set activation flag for the UMA data collection for this renderer process.
-  static void SetPolicyEnabled(bool enabled);
+  static void SetEnabled(bool enabled);
 
   // Returns any bookkeeping data about the HTTP header information for the
   // request identified by |request_id|. Any data returned should then be

[alexmos, 2015/06/11 20:17:48]

nit: there's no request_id passed to this function (anymore?), so maybe update
this comment.

[ncarter (slow), 2015/06/16 20:51:13]

Done.

   // passed to OnReceivedFirstChunk() with the first data chunk.
   static linked_ptr<SiteIsolationResponseMetaData> OnReceivedResponse(
       const GURL& frame_origin,
       const GURL& response_url,
       ResourceType resource_type,
       int origin_pid,
       const ResourceResponseInfo& info);
 
   // Examines the first chunk of network data in case response_url is registered
-  // as a cross-site document by DidReceiveResponse(). This records various
+  // as a cross-site document by OnReceivedResponse(). This records various
   // kinds of UMA data stats. This function is called only if the length of
   // received data is non-zero.
   static bool OnReceivedFirstChunk(
       const linked_ptr<SiteIsolationResponseMetaData>& resp_data,
       const char* payload,
       int length);
+ private:

[alexmos, 2015/06/11 20:17:48]

nit: blank line before private:?

[ncarter (slow), 2015/06/16 20:51:13]

Done.

+  FRIEND_TEST_ALL_PREFIXES(SiteIsolationStatsGathererTest, SniffForJS);
 
- private:
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, IsBlockableScheme);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, IsSameSite);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, IsValidCorsHeaderSet);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, SniffForHTML);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, SniffForXML);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, SniffForJSON);
-  FRIEND_TEST_ALL_PREFIXES(SiteIsolationPolicyTest, SniffForJS);
+  SiteIsolationStatsGatherer();  // Not instantiable.
 
+  // Imprecise JS sniffing; only appropriate for collecting UMA stat.
+  static bool SniffForJS(base::StringPiece data);
+
+  DISALLOW_COPY_AND_ASSIGN(SiteIsolationStatsGatherer);
+};
+
+// TODO(nick): Move this class into its own file.
+class CONTENT_EXPORT CrossSiteDocumentClassifier {
+ public:
   // Returns the representative mime type enum value of the mime type of
   // response. For example, this returns the same value for all text/xml mime
   // type families such as application/xml, application/rss+xml.
   static SiteIsolationResponseMetaData::CanonicalMimeType GetCanonicalMimeType(
       const std::string& mime_type);
 
   // Returns whether this scheme is a target of cross-site document
   // policy(XSDP). This returns true only for http://* and https://* urls.
   static bool IsBlockableScheme(const GURL& frame_origin);
 
   // Returns whether the two urls belong to the same sites.
   static bool IsSameSite(const GURL& frame_origin, const GURL& response_url);
 
   // Returns whether there's a valid CORS header for frame_origin.  This is
   // simliar to CrossOriginAccessControl::passesAccessControlCheck(), but we use
   // sites as our security domain, not origins.
   // TODO(dsjang): this must be improved to be more accurate to the actual CORS
   // specification. For now, this works conservatively, allowing XSDs that are
   // not allowed by actual CORS rules by ignoring 1) credentials and 2)
   // methods. Preflight requests don't matter here since they are not used to
   // decide whether to block a document or not on the client side.
   static bool IsValidCorsHeaderSet(const GURL& frame_origin,
                                    const GURL& website_origin,
                                    const std::string& access_control_origin);
 
   static bool SniffForHTML(base::StringPiece data);
   static bool SniffForXML(base::StringPiece data);
   static bool SniffForJSON(base::StringPiece data);
 
-  // TODO(dsjang): this is only needed for collecting UMA stat. Will be deleted
-  // when this class is used for actual blocking.
-  static bool SniffForJS(base::StringPiece data);
+ private:
+  CrossSiteDocumentClassifier();  // Not instantiable.
 
-  // Never needs to be constructed/destructed.
-  SiteIsolationPolicy() {}
-  ~SiteIsolationPolicy() {}
-
-  DISALLOW_COPY_AND_ASSIGN(SiteIsolationPolicy);
+  DISALLOW_COPY_AND_ASSIGN(CrossSiteDocumentClassifier);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_SITE_ISOLATION_POLICY_H_