Add an IPC method for Blink to call RapporService::RecordSample()

base/metrics/user_metrics.cc

 // Copyright 2014 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 "base/metrics/user_metrics.h"
 
 #include <vector>
 
 #include "base/lazy_instance.h"
 #include "base/threading/thread_checker.h"
 
 namespace base {
 namespace {
 
 // A helper class for tracking callbacks and ensuring thread-safety.
 class Callbacks {
  public:
   Callbacks() {}
 
   // Records the |action|.
   void Record(const std::string& action) {
     DCHECK(thread_checker_.CalledOnValidThread());
     for (size_t i = 0; i < callbacks_.size(); ++i) {
       callbacks_[i].Run(action);
     }
   }
 
+  void Record(const std::string& metric, const std::string& sample) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    if (!rappor_callback_.is_null())
+      rappor_callback_.Run(metric, sample);
+  }
+
   // Adds |callback| to the list of |callbacks_|.
   void AddCallback(const ActionCallback& callback) {
     DCHECK(thread_checker_.CalledOnValidThread());
     callbacks_.push_back(callback);
   }
 
   // Removes the first instance of |callback| from the list of |callbacks_|, if
   // there is one.
   void RemoveCallback(const ActionCallback& callback) {
     DCHECK(thread_checker_.CalledOnValidThread());
     for (size_t i = 0; i < callbacks_.size(); ++i) {
       if (callbacks_[i].Equals(callback)) {
         callbacks_.erase(callbacks_.begin() + i);
         return;
       }
     }
   }
 
+  void AddCallback(const RapporCallback& callback) {
+    DCHECK(thread_checker_.CalledOnValidThread());
+    DCHECK(rappor_callback_.is_null());
+    rappor_callback_ = callback;
+  }
+
  private:
   base::ThreadChecker thread_checker_;
   std::vector<ActionCallback> callbacks_;
+  RapporCallback rappor_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(Callbacks);
 };
 
 base::LazyInstance<Callbacks> g_callbacks = LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 void RecordAction(const UserMetricsAction& action) {
   g_callbacks.Get().Record(action.str_);
 }
 
 void RecordComputedAction(const std::string& action) {
   g_callbacks.Get().Record(action);
 }
 
+void RecordRappor(const std::string& metric, const std::string& sample) {
+  g_callbacks.Get().Record(metric, sample);
+}
+
 void AddActionCallback(const ActionCallback& callback) {
   g_callbacks.Get().AddCallback(callback);
 }
 
 void RemoveActionCallback(const ActionCallback& callback) {
   g_callbacks.Get().RemoveCallback(callback);
+}
 
+void AddRapporCallback(const RapporCallback& callback) {
+  g_callbacks.Get().AddCallback(callback);
 }
 
 }  // namespace base