Bug 533995: [GTK3] Native memory leak in gc.setBackground/setForeground

Free all strings returned by gtk_css_provider_to_string() to fix a
memory leak.

Change-Id: I94e45c2457bfbcf6970038f61926830c7d480f76
Signed-off-by: Eric Williams <ericwill@redhat.com>
diff --git a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
index 0f76b1a..a5e08f6 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT/gtk/org/eclipse/swt/widgets/Display.java
@@ -1942,6 +1942,7 @@
 	}
 	byte [] themeBuffer = new byte [length];
 	C.memmove (themeBuffer, str, length);
+	OS.g_free(str);
 	String cssOutput = new String (Converter.mbcsToWcs (themeBuffer));
 
 	// Parse the theme values based on the corresponding SWT value
@@ -2210,6 +2211,7 @@
 	int length = C.strlen (str);
 	byte [] buffer = new byte [length];
 	C.memmove (buffer, str, length);
+	OS.g_free(str);
 	String cssOutput = new String (Converter.mbcsToWcs (buffer));
 	String searched = "";
 	/*
@@ -2274,6 +2276,7 @@
 	int length = C.strlen (str);
 	byte [] buffer = new byte [length];
 	C.memmove (buffer, str, length);
+	OS.g_free(str);
 	String cssOutput = new String (Converter.mbcsToWcs (buffer));
 	String searched = "";
 	/*