Installer: Do not write "URL Protocol" to the ChromeHTML registry entry.

This means Chrome will no longer register itself as the handler for the
bogus "chromehtml" URL protocol. (Regular file associations should not
register the class name as a URL protocol.)

BUG=413051

Review URL: https://codereview.chromium.org/559253002

Cr-Commit-Position: refs/heads/master@{#294941}

chrome/installer/util/shell_util.cc

@@ -296,8 +296,6 @@ class RegistryEntry {
     chrome_html_prog_id.append(GetBrowserProgId(suffix));
     entries->push_back(new RegistryEntry(
         chrome_html_prog_id, dist->GetBrowserProgIdDesc()));
-    entries->push_back(new RegistryEntry(
-        chrome_html_prog_id, ShellUtil::kRegUrlProtocol, base::string16()));
     entries->push_back(new RegistryEntry(
         chrome_html_prog_id + ShellUtil::kRegDefaultIcon, icon_path));
     entries->push_back(new RegistryEntry(