Temporarily enable PlzNavigate to see perf bot results.

BUG=368813
TBR=clamy@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://chromium.googlesource.com/chromium/src/+/3d001c287618b8298e5b95bd98556a5beffc0316
Review-Url: https://codereview.chromium.org/2584093003
Cr-Commit-Position: refs/heads/master@{#439731}

content/public/common/browser_side_navigation_policy.cc

@@ -10,8 +10,7 @@
 namespace content {
 
 bool IsBrowserSideNavigationEnabled() {
-  return base::CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kEnableBrowserSideNavigation);
+  return true;
 }
 
 }  // namespace content