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 4605c8ddb1bed7a440923a41572674f201978d9f..be6e8fa222c15e651ce7b0f8d97ee5bd50ab116f 100644
--- a/chrome/browser/ui/views/frame/browser_view.h
+++ b/chrome/browser/ui/views/frame/browser_view.h
@@ -50,6 +50,7 @@
 
 class BookmarkBarView;
 class Browser;
+class BrowserViewHistogramHelper;
 class BrowserViewLayout;
 class ContentsLayoutManager;
 class DownloadShelfView;
@@ -439,6 +440,7 @@ 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;
@@ -715,6 +717,8 @@ class BrowserView : public BrowserWindow,
   std::unique_ptr<ExtensionKeybindingRegistryViews>
       extension_keybinding_registry_;
 
+  std::unique_ptr<BrowserViewHistogramHelper> histogram_helper_;
+
   mutable base::WeakPtrFactory<BrowserView> activate_modal_dialog_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserView);