PDF: Add UMA to track successful / failed PDF loads

chrome/renderer/plugins/plugin_uma.h

 // Copyright (c) 2011 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_RENDERER_PLUGINS_PLUGIN_UMA_H_
 #define CHROME_RENDERER_PLUGINS_PLUGIN_UMA_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 #include "url/gurl.h"
 
 // Used to send UMA data about missing plugins to UMA histogram server. Method
 // ReportPluginMissing should be called whenever plugin that is not available or
 // enabled is called. We try to determine plugin's type by requested mime type,
 // or, if mime type is unknown, by plugin's src url.
 class PluginUMAReporter {
  public:
   enum ReportType {
     MISSING_PLUGIN,
-    DISABLED_PLUGIN
+    DISABLED_PLUGIN,
   };
 
   // Make sure the enum list in tools/histogram/histograms.xml is updated with
   // any change in this list.
   enum PluginType {
     WINDOWS_MEDIA_PLAYER = 0,
     SILVERLIGHT = 1,
     REALPLAYER = 2,
     JAVA = 3,
     QUICKTIME = 4,
     OTHER = 5,  // This is obsolete and replaced by UNSUPPORTED_* types.
     UNSUPPORTED_MIMETYPE,
     UNSUPPORTED_EXTENSION,
     // NOTE: Add new unsupported types only immediately above this line.
     BROWSER_PLUGIN = 10,
     SHOCKWAVE_FLASH,
     WIDEVINE_CDM,
     // NOTE: Add new plugin types only immediately above this line.
     PLUGIN_TYPE_MAX
   };
 
+  // Must be kept in sync with PDFLoadStatus enum in histograms.xml.

[Ilya Sherman, 2017/05/08 17:59:57]

Please also document that this enum should be treated as append-only, since we
want time-invariant semantics for the histogram buckets.

[tommycli, 2017/05/08 18:16:17]

Done.

+  enum PDFLoadStatus {
+    LOADED_FULL_PAGE_PDF_WITH_PDFIUM = 0,
+    LOADED_EMBEDDED_PDF_WITH_PDFIUM = 1,
+    SHOWED_DISABLED_PLUGIN_PLACEHOLDER_FOR_EMBEDDED_PDF = 2,
+    PDF_LOAD_STATUS_MAX

[Ilya Sherman, 2017/05/08 17:59:57]

Optional nit: Typically, "max" is used as an alias for the last item in the
enum, whereas "count" is used to count the number of valid entries in the enum. 
So, I'd recommend "count" here.

[tommycli, 2017/05/08 18:16:17]

Done.

+  };
+
   // Sends UMA data, i.e. plugin's type.
   class UMASender {
    public:
     virtual ~UMASender() {}
     virtual void SendPluginUMA(ReportType report_type,
                                PluginType plugin_type) = 0;
   };
 
   // Returns singleton instance.
   static PluginUMAReporter* GetInstance();
 
+  static void ReportPDFLoadStatus(PDFLoadStatus status);
+
   void ReportPluginMissing(const std::string& plugin_mime_type,
                            const GURL& plugin_src);
 
   void ReportPluginDisabled(const std::string& plugin_mime_type,
                             const GURL& plugin_src);
 
  private:
   friend struct base::DefaultSingletonTraits<PluginUMAReporter>;
   friend class PluginUMATest;
 
@@ skipping 14 matching lines @@
   PluginType SrcToPluginType(const GURL& src);
   // Converts plugin's mime type to plugin type.
   PluginType MimeTypeToPluginType(const std::string& mime_type);
 
   std::unique_ptr<UMASender> report_sender_;
 
   DISALLOW_COPY_AND_ASSIGN(PluginUMAReporter);
 };
 
 #endif  // CHROME_RENDERER_PLUGINS_PLUGIN_UMA_H_