MD History: truncate title to 300 chars in C++ instead of JS

chrome/browser/ui/webui/log_web_ui_url_browsertest.cc

 // Copyright 2015 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/ui/webui/log_web_ui_url.h"
 
 #include <stdint.h>
 
 #include <vector>
 
@@ skipping 24 matching lines @@
  public:
   LogWebUIUrlTest() {}
   ~LogWebUIUrlTest() override {}
 
   std::vector<Bucket> GetSamples() {
     return histogram_tester_.GetAllSamples(webui::kWebUICreatedForUrl);
   }
 
   void SetUpOnMainThread() override {
     // Disable MD History to test non-MD history page.
-    MdHistoryUI::DisableForTesting();
+    MdHistoryUI::SetEnabledForTesting(false);
   }
 
  private:
   base::HistogramTester histogram_tester_;
 
   DISALLOW_COPY_AND_ASSIGN(LogWebUIUrlTest);
 };
 
 IN_PROC_BROWSER_TEST_F(LogWebUIUrlTest, TestHistoryFrame) {
   GURL history_frame_url(chrome::kChromeUIHistoryFrameURL);
@@ skipping 60 matching lines @@
   uint32_t extensions_frame_url_hash = base::Hash(extensions_frame_url.spec());
 
   EXPECT_THAT(GetSamples(), ElementsAre(Bucket(extensions_frame_url_hash, 1),
                                         Bucket(history_frame_url_hash, 2),
                                         Bucket(uber_frame_url_hash, 2),
                                         Bucket(uber_url_hash, 2)));
 }
 #endif
 
 }  // namespace webui