[Most Visited] Log suggestion provider to UMA

chrome/browser/search/most_visited_iframe_source.h

 // 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.
 
 #ifndef CHROME_BROWSER_SEARCH_MOST_VISITED_IFRAME_SOURCE_H_
 #define CHROME_BROWSER_SEARCH_MOST_VISITED_IFRAME_SOURCE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/search/iframe_source.h"
 
 // Serves HTML for displaying suggestions using iframes, e.g.
 // chrome-search://suggestion/loader.html
 class MostVisitedIframeSource : public IframeSource {
  public:
   MostVisitedIframeSource();
   virtual ~MostVisitedIframeSource();
 
   // Number of Most Visited elements on the NTP for logging purposes.
   static const int kNumMostVisited;
   // Name of the histogram keeping track of Most Visited clicks.
   static const char kMostVisitedHistogramName[];
+  // Format string to generate the name of the histogram keeping track of MV
+  // clicks specific to a provider.
+  static const char kMostVisitedHistogramWithProvider[];

[Alexei Svitkine (slow), 2013/12/12 22:15:44]

Instead of exposing this constant directly and having your tests use
stringprintf on it, how about making a function that formats the histogram?
Then, the string constant can be local in the .cc file and the test can call the
function.

[Mathieu, 2013/12/13 15:01:38]

Done.

 
   // Overridden from IframeSource. Public for testing.
   virtual void StartDataRequest(
       const std::string& path_and_query,
       int render_process_id,
       int render_view_id,
       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
 
  protected:
   // Overridden from IframeSource:
   virtual std::string GetSource() const OVERRIDE;
 
   virtual bool ServesPath(const std::string& path) const OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(MostVisitedIframeSource);
 };
 
 #endif  // CHROME_BROWSER_SEARCH_MOST_VISITED_IFRAME_SOURCE_H_