Fix compilation with Ozone build for chromium browser.

Compiling Error:

../../chrome/browser/shell_integration_linux.cc:294:13: error: unused function 'QuoteCommandLineForDesktopFileExec' [-Werror,-Wunused-function]
std::string QuoteCommandLineForDesktopFileExec(
            ^
../../chrome/browser/shell_integration_linux.cc:310:12: error: unused variable 'kDesktopEntry' [-Werror,-Wunused-const-variable]
const char kDesktopEntry[] = "Desktop Entry";
           ^
../../chrome/browser/shell_integration_linux.cc:312:12: error: unused variable 'kXdgOpenShebang' [-Werror,-Wunused-const-variable]
const char kXdgOpenShebang[] = "#!/usr/bin/env xdg-open";
           ^
3 errors generated.

The above mentioned function and variables are only used from GetNoDisplayFromDesktopFile,
only when support for GLIB is enabled.

Review URL: https://codereview.chromium.org/499823002

Cr-Commit-Position: refs/heads/master@{#291748}

chrome/browser/shell_integration_linux.cc

@@ -260,6 +260,7 @@ void DeleteShortcutInApplicationsMenu(
   LaunchXdgUtility(argv, &exit_code);
 }
 
+#if defined(USE_GLIB)
 // Quote a string such that it appears as one verbatim argument for the Exec
 // key in a desktop file.
 std::string QuoteArgForDesktopFileExec(const std::string& arg) {
@@ -310,6 +311,7 @@ std::string QuoteCommandLineForDesktopFileExec(
 const char kDesktopEntry[] = "Desktop Entry";
 
 const char kXdgOpenShebang[] = "#!/usr/bin/env xdg-open";
+#endif
 
 const char kXdgSettings[] = "xdg-settings";
 const char kXdgSettingsDefaultBrowser[] = "default-web-browser";