Add HTTPS specific UMA for data reduction proxy requests

BUG=374264

Review URL: https://codereview.chromium.org/688403002

Cr-Commit-Position: refs/heads/master@{#302701}

chrome/renderer/page_load_histograms.h

@@ -6,6 +6,7 @@
 #define CHROME_RENDERER_PAGE_LOAD_HISTOGRAMS_H_
 
 #include "base/basictypes.h"
+#include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
 #include "content/public/renderer/render_view_observer.h"
 
 namespace content {
@@ -45,6 +46,8 @@ class PageLoadHistograms : public content::RenderViewObserver {
   void LogPageLoadTime(const content::DocumentState* load_times,
                        const blink::WebDataSource* ds) const;
 
+  data_reduction_proxy::DataReductionProxyParams data_reduction_proxy_params_;
+
   DISALLOW_COPY_AND_ASSIGN(PageLoadHistograms);
 };