[Cronet] Make HistogramManager an abstract class to break dependency on native library.

components/cronet/android/cronet_loader.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/android/base_jni_registrar.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_registrar.h"
 #include "base/at_exit.h"
 #include "components/cronet/android/chromium_url_request.h"
 #include "components/cronet/android/chromium_url_request_context.h"
+#include "components/cronet/android/cronet_histogram_manager.h"
 #include "components/cronet/android/cronet_url_request.h"
 #include "components/cronet/android/cronet_url_request_context.h"
-#include "components/cronet/android/histogram_manager.h"
 #include "net/android/net_jni_registrar.h"
 #include "url/android/url_jni_registrar.h"
 #include "url/url_util.h"
 
 #if !defined(USE_ICU_ALTERNATIVES_ON_ANDROID)
 #include "base/i18n/icu_util.h"
 #endif
 
 namespace cronet {
 namespace {
 
 const base::android::RegistrationMethod kCronetRegisteredMethods[] = {
     {"BaseAndroid", base::android::RegisterJni},
-    {"ChromiumUrlRequest", cronet::ChromiumUrlRequestRegisterJni},
-    {"ChromiumUrlRequestContext", cronet::ChromiumUrlRequestContextRegisterJni},
-    {"CronetUrlRequest", cronet::CronetUrlRequestRegisterJni},
-    {"CronetUrlRequestContext", cronet::CronetUrlRequestContextRegisterJni},
-    {"HistogramManager", cronet::HistogramManagerRegisterJni},
+    {"ChromiumUrlRequest", ChromiumUrlRequestRegisterJni},
+    {"ChromiumUrlRequestContext", ChromiumUrlRequestContextRegisterJni},
+    {"CronetHistogramManager", CronetHistogramManagerRegisterJni},
+    {"CronetUrlRequest", CronetUrlRequestRegisterJni},
+    {"CronetUrlRequestContext", CronetUrlRequestContextRegisterJni},
     {"NetAndroid", net::android::RegisterJni},
     {"UrlAndroid", url::android::RegisterJni},
 };
 
 base::AtExitManager* g_at_exit_manager = NULL;
 
 }  // namespace
 
 // Checks the available version of JNI. Also, caches Java reflection artifacts.
 jint CronetOnLoad(JavaVM* vm, void* reserved) {
@@ skipping 21 matching lines @@
 }
 
 void CronetOnUnLoad(JavaVM* jvm, void* reserved) {
   if (g_at_exit_manager) {
     delete g_at_exit_manager;
     g_at_exit_manager = NULL;
   }
 }
 
 }  // namespace cronet