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

components/cronet.gypi

 # 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.
 
 {
   'conditions': [
     ['OS=="android"', {
       # TODO(mef): Figure out what needs to be done for gn script.
       'targets': [
         {
           'target_name': 'cronet_jni_headers',
           'type': 'none',
           'sources': [
+            'cronet/android/java/src/org/chromium/net/CronetHistogramManager.java',
             'cronet/android/java/src/org/chromium/net/CronetUrlRequest.java',
             'cronet/android/java/src/org/chromium/net/CronetUrlRequestContext.java',
             'cronet/android/java/src/org/chromium/net/ChromiumUrlRequest.java',
             'cronet/android/java/src/org/chromium/net/ChromiumUrlRequestContext.java',
-            'cronet/android/java/src/org/chromium/net/HistogramManager.java',
           ],
           'variables': {
             'jni_gen_package': 'cronet',
           },
           'includes': [ '../build/jni_generator.gypi' ],
         },
         {
           'target_name': 'cronet_url_request_java',
           'type': 'none',
           'variables': {
@@ skipping 86 matching lines @@
           'sources': [
             'cronet/url_request_context_config.cc',
             'cronet/url_request_context_config.h',
             'cronet/url_request_context_config_list.h',
             'cronet/android/chromium_url_request.cc',
             'cronet/android/chromium_url_request.h',
             'cronet/android/chromium_url_request_error_list.h',
             'cronet/android/chromium_url_request_priority_list.h',
             'cronet/android/chromium_url_request_context.cc',
             'cronet/android/chromium_url_request_context.h',
+            'cronet/android/cronet_histogram_manager.cc',
+            'cronet/android/cronet_histogram_manager.h',
             'cronet/android/cronet_loader.cc',
             'cronet/android/cronet_loader.h',
             'cronet/android/cronet_url_request.cc',
             'cronet/android/cronet_url_request.h',
             'cronet/android/cronet_url_request_adapter.cc',
             'cronet/android/cronet_url_request_adapter.h',
             'cronet/android/cronet_url_request_context.cc',
             'cronet/android/cronet_url_request_context.h',
             'cronet/android/cronet_url_request_context_adapter.cc',
             'cronet/android/cronet_url_request_context_adapter.h',
-            'cronet/android/histogram_manager.cc',
-            'cronet/android/histogram_manager.h',
             'cronet/android/url_request_adapter.cc',
             'cronet/android/url_request_adapter.h',
             'cronet/android/url_request_context_adapter.cc',
             'cronet/android/url_request_context_adapter.h',
             'cronet/android/wrapped_channel_upload_element_reader.cc',
             'cronet/android/wrapped_channel_upload_element_reader.h',
           ],
           'cflags': [
             '-DLOGGING=1',
             '-fdata-sections',
@@ skipping 40 matching lines @@
           'type': 'none',
           'dependencies': [
             'cronet_url_request_context_config_list',
             'cronet_version',
           ],
           'variables': {
             'java_in_dir': 'cronet/android/java',
             'javac_includes': [
               '**/ChunkedWritableByteChannel.java',
               '**/ExtendedResponseInfo.java',
+              '**/HistogramManager.java',
               '**/HttpUrlConnection*.java',
               '**/HttpUrlRequest*.java',
               '**/ResponseInfo.java',
               '**/ResponseTooLargeException.java',
               '**/UrlRequest.java',
               '**/UrlRequestContext.java',
               '**/UrlRequestContextConfig.java',
               '**/UrlRequestContextConfigList.java',
               '**/UrlRequestException.java',
               '**/UrlRequestListener.java',
@@ skipping 16 matching lines @@
           ],
           'variables': {
             'java_in_dir': 'cronet/android/java',
             'javac_includes': [
               '**/ChromiumAsyncUrlRequest.java',
               '**/ChromiumUrlRequest.java',
               '**/ChromiumUrlRequestContext.java',
               '**/ChromiumUrlRequestError.java',
               '**/ChromiumUrlRequestFactory.java',
               '**/ChromiumUrlRequestPriority.java',
+              '**/CronetHistogramManager.java',
               '**/CronetResponseInfo.java',
               '**/CronetUrlRequest.java',
               '**/CronetUrlRequestContext.java',
               '**/CronetUrlRequestFactory.java',
-              '**/HistogramManager.java',
               '**/RequestPriority.java',
               '**/urlconnection/CronetInputStream.java',
               '**/urlconnection/CronetHttpURLConnection.java',
               '**/urlconnection/CronetHttpURLStreamHandler.java',
               '**/urlconnection/CronetURLStreamHandlerFactory.java',
               '**/urlconnection/MessageLoop.java',
             ],
           },
           'includes': [ '../build/java.gypi' ],
         },
@@ skipping 269 matching lines @@
               'files': [
                 '<(SHARED_LIB_DIR)/<(native_lib)',
               ],
             },
           ],
         },
       ],
     }],  # OS=="android" and use_icu_alternatives_on_android==1
   ],
 }