Isolate initiation counts for downloads to their own histograms and improve

content/browser/download/download_stats.h

Index: content/browser/download/download_stats.h
diff --git a/content/browser/download/download_stats.h b/content/browser/download/download_stats.h
index ecf87f30f9e1172a8a45a4cb03146e2cd9b8b3c0..f9f244b8573a3e43331f023f9ddb9b2d10c0e3fd 100644
--- a/content/browser/download/download_stats.h
+++ b/content/browser/download/download_stats.h
@@ -24,30 +24,15 @@ namespace download_stats {
 // We keep a count of how often various events occur in the
 // histogram "Download.Counts".
 enum DownloadCountTypes {
-  // The download was initiated by navigating to a URL (e.g. by user
-  // click).
-  // This is now unused, but left around so that the values don't change.
-  INITIATED_BY_NAVIGATION_COUNT = 0,
-
-  // The download was initiated by invoking a context menu within a page.
-  // This is now unused, but left around so that the values don't change.
-  INITIATED_BY_CONTEXT_MENU_COUNT,
-
-  // The download was initiated when the SavePackage system rejected
-  // a Save Page As ... by returning false from
-  // SavePackage::IsSaveableContents().
-  INITIATED_BY_SAVE_PACKAGE_FAILURE_COUNT,
-
-  // The download was initiated by a drag and drop from a drag-and-drop
-  // enabled web application.
-  INITIATED_BY_DRAG_N_DROP_COUNT,
-
-  // The download was initiated by explicit RPC from the renderer process
-  // (e.g. by Alt-click).
-  INITIATED_BY_RENDERER_COUNT,
-
-  // Downloads that made it to DownloadResourceHandler -- all of the
-  // above minus those blocked by DownloadThrottlingResourceHandler.
+  // Stale enum values left around so that values passed to UMA don't
+  // change.
+  DOWNLOAD_COUNT_UNUSED_0 = 0,
+  DOWNLOAD_COUNT_UNUSED_1,
+  DOWNLOAD_COUNT_UNUSED_2,
+  DOWNLOAD_COUNT_UNUSED_3,
+  DOWNLOAD_COUNT_UNUSED_4,
+
+  // Downloads that made it to DownloadResourceHandler
   UNTHROTTLED_COUNT,
 
   // Downloads that actually complete.
@@ -81,8 +66,34 @@ enum DownloadCountTypes {
   DOWNLOAD_COUNT_TYPES_LAST_ENTRY
 };
 
+enum DownloadSource {
+  // The download was initiated when the SavePackage system rejected
+  // a Save Page As ... by returning false from
+  // SavePackage::IsSaveableContents().
+  INITIATED_BY_SAVE_PACKAGE_ON_NON_HTML = 0,
+
+  // The download was initiated by a drag and drop from a drag-and-drop
+  // enabled web application.
+  INITIATED_BY_DRAG_N_DROP,
+
+  // The download was initiated by explicit RPC from the renderer process
+  // (e.g. by Alt-click) through the IPC ViewHostMsg_DownloadUrl.
+  INITIATED_BY_RENDERER,
+
+  // The download was initiated by a renderer or plugin process through
+  // the IPC ViewHostMsg_SaveURLAs; currently this is only used by the
+  // Pepper plugin API.
+  INITIATED_BY_PEPPER_SAVE,
+
+  DOWNLOAD_SOURCE_LAST_ENTRY
+};
+
+
 // Increment one of the above counts.
-CONTENT_EXPORT void RecordDownloadCount(DownloadCountTypes type);
+void RecordDownloadCount(DownloadCountTypes type);
+
+// Record initiation of a download from a specific source.
+void RecordDownloadSource(DownloadSource source);
 
 // Record COMPLETED_COUNT and how long the download took.
 void RecordDownloadCompleted(const base::TimeTicks& start, int64 download_len);