Fix global variable name to follow style guide

components/keyed_service/ios/browser_state_helper.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 "components/keyed_service/ios/browser_state_helper.h"
 
 #include "base/logging.h"
 #include "base/supports_user_data.h"
 #include "ios/web/public/browser_state.h"
 
@@ skipping 13 matching lines @@
 // methods that take a base::SupportsUserData need to discriminate
 // between the two objects.
 //
 // If the base::SupportsUserData is a web::BrowserState then the public
 // method web::BrowserState::FromSupportsUserData can do the conversion
 // safely. If this method fails then context is content::BrowserContext
 // and the methods defined below allow the embedder to provides helper
 // to find the associated web::BrowserState (there is a 1:1 mapping).
 
 namespace {
-BrowserStateFromContextFn gBrowserStateFromContext = nullptr;
+BrowserStateFromContextFn g_browser_state_from_context = nullptr;
 }  // namespace
 
 void SetBrowserStateFromContextHelper(BrowserStateFromContextFn helper) {
-  gBrowserStateFromContext = helper;
+  g_browser_state_from_context = helper;
 }
 
 web::BrowserState* BrowserStateFromContext(base::SupportsUserData* context) {
   web::BrowserState* state = nullptr;
   if (context) {
     state = web::BrowserState::FromSupportsUserData(context);
-    if (!state && gBrowserStateFromContext)
-      state = gBrowserStateFromContext(context);
+    if (!state && g_browser_state_from_context)
+      state = g_browser_state_from_context(context);
     DCHECK(state) << "cannot convert context to web::BrowserState";
   }
   return state;
 }