Remove DocumentMode usage histogram.

chrome/browser/android/feature_utilities.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 "chrome/browser/android/feature_utilities.h"
 
 #include "jni/FeatureUtilities_jni.h"
 
 using base::android::JavaParamRef;
 
 namespace {
-bool document_mode_enabled = false;
 bool custom_tab_visible = false;
 bool is_in_multi_window_mode = false;
 } // namespace
 
 namespace chrome {
 namespace android {
 
-RunningModeHistogram GetDocumentModeValue() {
-  return document_mode_enabled ? RUNNING_MODE_DOCUMENT_MODE :
-      RUNNING_MODE_TABBED_MODE;
-}
-
 CustomTabsVisibilityHistogram GetCustomTabsVisibleValue() {
   return custom_tab_visible ? VISIBLE_CUSTOM_TAB :
       VISIBLE_CHROME_TAB;
 }
 
 bool GetIsInMultiWindowModeValue() {
   return is_in_multi_window_mode;
 }
 
 } // namespace android
 } // namespace chrome
 
-static void SetDocumentModeEnabled(JNIEnv* env,
-                                   const JavaParamRef<jclass>& clazz,
-                                   jboolean enabled) {
-  document_mode_enabled = enabled;
-}
-
 static void SetCustomTabVisible(JNIEnv* env,
                                 const JavaParamRef<jclass>& clazz,
                                 jboolean visible) {
   custom_tab_visible = visible;
 }
 
 static void SetIsInMultiWindowMode(JNIEnv* env,
                                    const JavaParamRef<jclass>& clazz,
                                    jboolean j_is_in_multi_window_mode) {
   is_in_multi_window_mode = j_is_in_multi_window_mode;
 }
 
 bool RegisterFeatureUtilities(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }