Add UMA stats for per-child file permissions count

content/browser/child_process_security_policy.cc

 // Copyright (c) 2011 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.
 
 #include "content/browser/child_process_security_policy.h"
 
 #include "base/file_path.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/platform_file.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "content/public/common/bindings_policy.h"
 #include "content/public/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "net/url_request/url_request.h"
 
 static const int kReadFilePermissions =
     base::PLATFORM_FILE_OPEN |
     base::PLATFORM_FILE_READ |
     base::PLATFORM_FILE_EXCLUSIVE_READ |
     base::PLATFORM_FILE_ASYNC;
 
 static const int kEnumerateDirectoryPermissions =
     kReadFilePermissions |
     base::PLATFORM_FILE_ENUMERATE;
 
 // The SecurityState class is used to maintain per-child process security state
 // information.
 class ChildProcessSecurityPolicy::SecurityState {
  public:
   SecurityState()
     : enabled_bindings_(0),
       can_read_raw_cookies_(false) { }
   ~SecurityState() {
     scheme_policy_.clear();
+    UMA_HISTOGRAM_COUNTS("ChildProcessSecurityPolicy.PerChildFilePermissions",
+                         file_permissions_.size());
   }
 
   // Grant permission to request URLs with the specified scheme.
   void GrantScheme(const std::string& scheme) {
     scheme_policy_[scheme] = true;
   }
 
   // Revoke permission to request URLs with the specified scheme.
   void RevokeScheme(const std::string& scheme) {
     scheme_policy_[scheme] = false;
   }
 
   // Grant certain permissions to a file.
   void GrantPermissionsForFile(const FilePath& file, int permissions) {
-    file_permissions_[file.StripTrailingSeparators()] |= permissions;
+    FilePath stripped = file.StripTrailingSeparators();
+    file_permissions_[stripped] |= permissions;
+    UMA_HISTOGRAM_COUNTS("ChildProcessSecurityPolicy.FilePermissionPathLength",
+                         stripped.value().size());
   }
 
   // Revokes all permissions granted to a file.
   void RevokeAllPermissionsForFile(const FilePath& file) {
     file_permissions_.erase(file.StripTrailingSeparators());
   }
 
   void GrantBindings(int bindings) {
     enabled_bindings_ |= bindings;
   }
@@ skipping 375 matching lines @@
   security_state_[child_id] = new SecurityState();
 }
 
 bool ChildProcessSecurityPolicy::ChildProcessHasPermissionsForFile(
     int child_id, const FilePath& file, int permissions) {
   SecurityStateMap::iterator state = security_state_.find(child_id);
   if (state == security_state_.end())
     return false;
   return state->second->HasPermissionsForFile(file, permissions);
 }