Add Startup.BrowserView.FirstPaint / .CompositingEnded histograms.

chrome/browser/ui/views/frame/browser_view.h

Index: chrome/browser/ui/views/frame/browser_view.h
diff --git a/chrome/browser/ui/views/frame/browser_view.h b/chrome/browser/ui/views/frame/browser_view.h
index e0f70e86e4deea5d96c053ee51672dd3dcfc6f51..c1a2b4141ca7d115b682ab77f2c12ce570f4f9f6 100644
--- a/chrome/browser/ui/views/frame/browser_view.h
+++ b/chrome/browser/ui/views/frame/browser_view.h
@@ -19,6 +19,7 @@
 #include "chrome/browser/devtools/devtools_window.h"
 #include "chrome/browser/extensions/extension_commands_global_registry.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
+#include "chrome/browser/metrics/browser_window_histogram_helper.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_context.h"
@@ -438,6 +439,7 @@ class BrowserView : public BrowserWindow,
   void OnGestureEvent(ui::GestureEvent* event) override;
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;
+  void PaintChildren(const ui::PaintContext& context) override;
   void ChildPreferredSizeChanged(View* child) override;
   void GetAccessibleNodeData(ui::AXNodeData* node_data) override;
   void OnThemeChanged() override;
@@ -712,6 +714,8 @@ class BrowserView : public BrowserWindow,
   std::unique_ptr<ExtensionKeybindingRegistryViews>
       extension_keybinding_registry_;
 
+  std::unique_ptr<BrowserWindowHistogramHelper> histogram_helper_;
+
   mutable base::WeakPtrFactory<BrowserView> activate_modal_dialog_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserView);