Convert tests to use the non-deprecated WebContentsObserver navigation methods.

chrome/browser/ui/browser_browsertest.cc

Index: chrome/browser/ui/browser_browsertest.cc
diff --git a/chrome/browser/ui/browser_browsertest.cc b/chrome/browser/ui/browser_browsertest.cc
index 7f6fa033d5c58ddc9102abb1a97b718c9ba352ba..0fd477c7073a0737e50615f004a0262c4af0aa38 100644
--- a/chrome/browser/ui/browser_browsertest.cc
+++ b/chrome/browser/ui/browser_browsertest.cc
@@ -283,11 +283,23 @@ class RenderViewSizeObserver : public content::WebContentsObserver {
         render_view_host->GetWidget()->GetView()->GetViewBounds().size();
   }
 
+  void DidStartNavigationToPendingEntry(
+      const GURL& url,
+      content::ReloadType reload_type) override {
+    // TODO: remove this method when PlzNavigate is turned on by default.
+    if (!content::IsBrowserSideNavigationEnabled())
+      Resize();
+  }
+
   // Enlarge WebContentsView by |wcv_resize_insets_| while the navigation entry
   // is pending.
-  void DidStartNavigationToPendingEntry(
-      const GURL& url,
-      content::ReloadType reload_type) override {
+  void DidStartNavigation(
+      content::NavigationHandle* navigation_handle) override {
+    if (content::IsBrowserSideNavigationEnabled())
+      Resize();
+  }
+
+  void Resize() {
     if (wcv_resize_insets_.IsEmpty())
       return;
     // Resizing the main browser window by |wcv_resize_insets_| will
@@ -327,7 +339,7 @@ class RenderViewSizeObserver : public content::WebContentsObserver {
   typedef std::map<content::RenderViewHost*, Sizes> RenderViewSizes;
   RenderViewSizes render_view_sizes_;
   // Enlarge WebContentsView by this size insets in
-  // DidStartNavigationToPendingEntry.
+  // DidStartNavigation.
   gfx::Size wcv_resize_insets_;
   BrowserWindow* browser_window_;  // Weak ptr.