[chrome] Default the user-defined empty ctor and dtor where possible

I need an owner's approval please for changes under:
['chrome/browser/sessions', 'chrome/browser/ui', 'chrome/browser/ui/tabs', 'chrome/browser/ui/toolbar', 'chrome/browser/ui/window_sizer']

This is a mechanical change. There are a few instances of empty
user-defined constructors and destructors left in the /chrome code
which can be defaulted.

This CL was uploaded by git cl split.

[email protected]

Bug: 381119547
Change-Id: I30ac0b1b9f94f54b41956a10621c30eccaab62c8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6056639
Reviewed-by: Darryl James <[email protected]>
Code-Coverage: [email protected] <[email protected]>
Commit-Queue: Darryl James <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1389200}
diff --git a/chrome/browser/ui/browser_live_tab_context.h b/chrome/browser/ui/browser_live_tab_context.h
index 1b9cbcb..fa9ac50 100644
--- a/chrome/browser/ui/browser_live_tab_context.h
+++ b/chrome/browser/ui/browser_live_tab_context.h
@@ -41,7 +41,7 @@
   BrowserLiveTabContext(const BrowserLiveTabContext&) = delete;
   BrowserLiveTabContext& operator=(const BrowserLiveTabContext&) = delete;
 
-  ~BrowserLiveTabContext() override {}
+  ~BrowserLiveTabContext() override = default;
 
   // Overridden from LiveTabContext:
   void ShowBrowserWindow() override;