Support viewport in content_shell.

Viewport preferences are overridden even with the --enable-viewport flag passed in.

BUG=343993

Review URL: https://codereview.chromium.org/166033008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252161 0039d316-1c4b-4281-b951-d872f2087c98

content/shell/common/webkit_test_helpers.cc

@@ -108,7 +108,6 @@ void ApplyLayoutTestDefaultPreferences(WebPreferences* prefs) {
 #if defined(OS_ANDROID)
   prefs->text_autosizing_enabled = false;
 #endif
-  prefs->viewport_enabled = false;
 }
 
 base::FilePath GetWebKitRootDirFilePath() {