Update most ScopedObserver declarations in //chrome/browser

Bug: 998625
Change-Id: I239558c07ce10166b82a2b886ef08a1d4ede56f2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1817333
Reviewed-by: Scott Violet <[email protected]>
Commit-Queue: Evan Stade <[email protected]>
Cr-Commit-Position: refs/heads/master@{#699035}
diff --git a/chrome/browser/metrics/browser_window_histogram_helper.h b/chrome/browser/metrics/browser_window_histogram_helper.h
index c0bd5aac..648f3823 100644
--- a/chrome/browser/metrics/browser_window_histogram_helper.h
+++ b/chrome/browser/metrics/browser_window_histogram_helper.h
@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "base/scoped_observer.h"
 #include "base/time/time.h"
+#include "ui/compositor/compositor.h"
 #include "ui/compositor/compositor_observer.h"
 
 // Class that encapsulates logic of recording
@@ -37,7 +38,7 @@
   void OnCompositingEnded(ui::Compositor* compositor) override;
   void OnCompositingShuttingDown(ui::Compositor* compositor) override;
 
-  ScopedObserver<ui::Compositor, ui::CompositorObserver> scoped_observer_;
+  ScopedObserver<ui::Compositor, ui::CompositorObserver> scoped_observer_{this};
 
   DISALLOW_COPY_AND_ASSIGN(BrowserWindowHistogramHelper);
 };