Use a placeholder instead of the default plugin for missing plug-ins on Mac and Linux.

chrome/browser/default_plugin_uitest.cc

Index: chrome/browser/default_plugin_uitest.cc
diff --git a/chrome/browser/default_plugin_uitest.cc b/chrome/browser/default_plugin_uitest.cc
index 5c6153167a37cca426634f973ab0e5ff8fc7f6d7..e0edc6e27fb390b6b40b81d3e0d9969bea54a351 100644
--- a/chrome/browser/default_plugin_uitest.cc
+++ b/chrome/browser/default_plugin_uitest.cc
@@ -17,11 +17,7 @@ class DefaultPluginUITest : public UITest {
 };
 
 #if defined(OS_WIN)
-#define MAYBE_DefaultPluginLoadTest DefaultPluginLoadTest
-#else
-#define MAYBE_DefaultPluginLoadTest DefaultPluginLoadTest
-#endif
-TEST_F(DefaultPluginUITest, MAYBE_DefaultPluginLoadTest) {
+TEST_F(DefaultPluginUITest, DefaultPluginLoadTest) {
   // Open page with default plugin.
   FilePath test_file(test_data_directory_);
   test_file = test_file.AppendASCII("default_plugin.html");
@@ -36,3 +32,4 @@ TEST_F(DefaultPluginUITest, MAYBE_DefaultPluginLoadTest) {
       L"document.getElementById('result').innerHTML)", &out));
   ASSERT_EQ(L"DONE", out);
 }
+#endif