gdiplus: Add GdipSetCustomLineCapBaseInset implementation.

dlls/gdiplus/customlinecap.c

@@ -220,14 +220,14 @@ GpStatus WINGDIPAPI GdipGetCustomLineCapBaseInset(GpCustomLineCap* custom,
 GpStatus WINGDIPAPI GdipSetCustomLineCapBaseInset(GpCustomLineCap* custom,
     REAL inset)
 {
-    static int calls;
-
     TRACE("(%p,%0.2f)\n", custom, inset);
 
-    if(!(calls++))
-        FIXME("not implemented\n");
+    if(!custom)
+        return InvalidParameter;
 
-    return NotImplemented;
+    custom->inset = inset;
+
+    return Ok;
 }
 
 /*FIXME: LineJoin completely ignored now */

dlls/gdiplus/tests/customlinecap.c

@@ -165,6 +165,14 @@ static void test_inset(void)
     expect(Ok, stat);
     expectf(0.0, inset);
 
+    stat = GdipSetCustomLineCapBaseInset(custom, 2.0);
+    expect(Ok, stat);
+
+    inset = (REAL)0xdeadbeef;
+    stat = GdipGetCustomLineCapBaseInset(custom, &inset);
+    expect(Ok, stat);
+    ok(inset == 2.0, "Unexpected inset value %f\n", inset);
+
     GdipDeleteCustomLineCap(custom);
     GdipDeletePath(path);
 }