Reuse ReportPDFLoadStatus() in ChromeMimeHandlerViewGuestDelegate.

Reuse ReportPDFLoadStatus() to report the PDF.LoadStatus UMA, instead of
doing it manually.

Change-Id: I92943fdf21b3a5bc800f2eab42cc1154e95bbd7b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2163747Reviewed-by: Tommy Li <tommycli@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762453}

chrome/browser/guest_view/mime_handler_view/chrome_mime_handler_view_guest_delegate.cc

@@ -6,7 +6,6 @@
 
 #include <utility>
 
-#include "base/metrics/histogram_functions.h"
 #include "chrome/browser/renderer_context_menu/render_view_context_menu.h"
 #include "chrome/common/pdf_util.h"
 #include "components/renderer_context_menu/context_menu_delegate.h"
@@ -37,11 +36,10 @@ void ChromeMimeHandlerViewGuestDelegate::RecordLoadMetric(
     const std::string& mime_type) {
   if (mime_type != kPDFMimeType)
     return;
-  base::UmaHistogramEnumeration(
-      "PDF.LoadStatus",
-      in_main_frame ? PDFLoadStatus::kLoadedFullPagePdfWithPdfium
-                    : PDFLoadStatus::kLoadedEmbeddedPdfWithPdfium,
-      PDFLoadStatus::kPdfLoadStatusCount);
+
+  ReportPDFLoadStatus(in_main_frame
+                          ? PDFLoadStatus::kLoadedFullPagePdfWithPdfium
+                          : PDFLoadStatus::kLoadedEmbeddedPdfWithPdfium);
 }
 
 }  // namespace extensions