Enable SiteEngagementEvictionPolicy behind --enable-site-eviction-policy flag.

content/public/browser/content_browser_client.cc

Index: content/public/browser/content_browser_client.cc
diff --git a/content/public/browser/content_browser_client.cc b/content/public/browser/content_browser_client.cc
index a9e7d2eda924cb554e2555f18e20283da04fdfc2..8f92ff3fabacd152d8a9531ad524f1f139266dd2 100644
--- a/content/public/browser/content_browser_client.cc
+++ b/content/public/browser/content_browser_client.cc
@@ -7,6 +7,7 @@
 #include "base/files/file_path.h"
 #include "content/public/browser/client_certificate_delegate.h"
 #include "content/public/common/sandbox_type.h"
+#include "storage/browser/quota/quota_manager.h"
 #include "ui/gfx/image/image_skia.h"
 #include "url/gurl.h"
 
@@ -215,6 +216,12 @@ QuotaPermissionContext* ContentBrowserClient::CreateQuotaPermissionContext() {
   return nullptr;
 }
 
+scoped_ptr<storage::QuotaEvictionPolicy>
+ContentBrowserClient::GetTemporaryStorageEvictionPolicy(
+    content::BrowserContext* context) {
+  return scoped_ptr<storage::QuotaEvictionPolicy>();
+}
+
 void ContentBrowserClient::SelectClientCertificate(
     WebContents* web_contents,
     net::SSLCertRequestInfo* cert_request_info,