Remove usage of Tab's |url| property from TabUsageRecorder.

ios/chrome/browser/metrics/tab_usage_recorder.mm

 // Copyright 2013 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 "ios/chrome/browser/metrics/tab_usage_recorder.h"
 
 #include "base/metrics/histogram_macros.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/metrics/previous_session_info.h"
 #import "ios/chrome/browser/tabs/tab.h"
@@ skipping 276 matching lines @@
 
 void TabUsageRecorder::ResetEvictedTab() {
   evicted_tab_ = NULL;
   evicted_tab_state_ = IN_MEMORY;
   evicted_tab_reload_start_time_ = base::TimeTicks();
 }
 
 bool TabUsageRecorder::ShouldIgnoreTab(Tab* tab) {
   // Do not count chrome:// urls to avoid data noise.  For example, if they were
   // counted, every new tab created would add noise to the page load count.
-  return [tab url].SchemeIs(kChromeUIScheme);
+  return tab.lastCommittedURL.SchemeIs(kChromeUIScheme);

[kkhorimoto, 2017/04/14 20:40:47]

chrome:// URLs are never pending, so lastCommitted should be sufficient.

[Eugene But (OOO till 7-30), 2017/04/14 21:48:09]

WebUI can be a pending URL, so maybe we should check both pending and last
committed?

[kkhorimoto, 2017/05/31 23:06:17]

Done.

 }
 
 bool TabUsageRecorder::TabAlreadyEvicted(Tab* tab) {
   base::WeakNSObject<Tab> weak_tab(tab);
   auto tab_item = evicted_tabs_.find(weak_tab);
   return tab_item != evicted_tabs_.end();
 }
 
 TabUsageRecorder::TabStateWhenSelected TabUsageRecorder::ExtractTabState(
     Tab* tab) {
@@ skipping 19 matching lines @@
 }
 
 void TabUsageRecorder::ClearDeletedTabs() {
   base::WeakNSObject<Tab> empty_tab(nil);
   auto tab_item = evicted_tabs_.find(empty_tab);
   while (tab_item != evicted_tabs_.end()) {
     evicted_tabs_.erase(empty_tab);
     tab_item = evicted_tabs_.find(empty_tab);
   }
 }