Add stats collection for telemetry startup.warm.blank_page test.

components/html_viewer/html_document.h

Index: components/html_viewer/html_document.h
diff --git a/components/html_viewer/html_document.h b/components/html_viewer/html_document.h
index 926e503cfcbdad67da868f85cb1c7d4ff084e2a3..eb20f46eeb89a291d4060df4f914a387cfec9772 100644
--- a/components/html_viewer/html_document.h
+++ b/components/html_viewer/html_document.h
@@ -22,6 +22,7 @@
 #include "mojo/application/public/interfaces/application.mojom.h"
 #include "mojo/application/public/interfaces/content_handler.mojom.h"
 #include "mojo/services/network/public/interfaces/url_loader.mojom.h"
+#include "mojo/services/tracing/public/interfaces/tracing.mojom.h"
 #include "third_party/WebKit/public/web/WebFrameClient.h"
 #include "third_party/WebKit/public/web/WebSandboxFlags.h"
 #include "third_party/WebKit/public/web/WebViewClient.h"
@@ -114,10 +115,12 @@ class HTMLDocument : public blink::WebViewClient,
                                       const blink::WebString& source_name,
                                       unsigned source_line,
                                       const blink::WebString& stack_trace);
+  virtual void didHandleOnloadEvents(blink::WebLocalFrame* frame);
   virtual void didFinishLoad(blink::WebLocalFrame* frame);
   virtual void didNavigateWithinPage(blink::WebLocalFrame* frame,
                                      const blink::WebHistoryItem& history_item,
                                      blink::WebHistoryCommitType commit_type);
+  virtual void didFirstVisuallyNonEmptyLayout(blink::WebLocalFrame* frame);
   virtual blink::WebEncryptedMediaClient* encryptedMediaClient();
 
  private:
@@ -189,6 +192,10 @@ class HTMLDocument : public blink::WebViewClient,
 
   DeleteCallback delete_callback_;
 
+  // This object is only valid in the context of performance tests.
+  tracing::StartupPerformanceDataCollectorPtr
+      startup_performance_data_collector_;
+
   DISALLOW_COPY_AND_ASSIGN(HTMLDocument);
 };