Move workbench running check in ColorManager to prevent SWT errors wh…

…en headless

This change adjusts the check added for Eclipze bugzilla 546205 ticket.
The check for running workbench is now done at the start of ColorManager.initializeDefaults(),
to prevent the creation of an SWT Display object when in headless mode.

See: https://bugs.eclipse.org/bugs//show_bug.cgi?id=546205

Fixes: #1486

ui/org.eclipse.pde.ui/src/org/eclipse/pde/internal/ui/editor/text/ColorManager.java

@@ -48,6 +48,9 @@ public static IColorManager getDefault() {
 	}
 
 	public static void initializeDefaults(IPreferenceStore store) {
+		if (!PlatformUI.isWorkbenchRunning()) {
+			return;
+		}
 		PreferenceConverter.setDefault(store, P_DEFAULT, DEFAULT);
 		PreferenceConverter.setDefault(store, P_PROC_INSTR, PROC_INSTR);
 		PreferenceConverter.setDefault(store, P_STRING, STRING);
@@ -61,9 +64,6 @@ public static void initializeDefaults(IPreferenceStore store) {
 		PreferenceConverter.setDefault(store, P_HEADER_ATTRIBUTES, HEADER_ATTRIBUTES);
 		store.setDefault(P_HEADER_ATTRIBUTES + IPDEColorConstants.P_ITALIC_SUFFIX, true);
 		PreferenceConverter.setDefault(store, P_HEADER_ASSIGNMENT, HEADER_ASSIGNMENT);
-		if (!PlatformUI.isWorkbenchRunning()) {
-			return;
-		}
 		try {
 			Display display = PlatformUI.getWorkbench().getDisplay();
 			Runnable runnable = () -> {