Adding an option to render only the shadow in SkDropShadowImageFilter

tests/RecordDrawTest.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
 #include "RecordTestUtils.h"
 
@@ skipping 216 matching lines @@
 // This also now serves as a regression test for crbug.com/418417.  We used to adjust the
 // bounds for the saveLayer, clip, and restore to be greater than the bounds of the picture.
 // (We were applying the saveLayer paint to the bounds after restore, which makes no sense.)
 DEF_TEST(RecordDraw_SaveLayerAffectsClipBounds, r) {
     SkRecord record;
     SkRecorder recorder(&record, 50, 50);
 
     // We draw a rectangle with a long drop shadow.  We used to not update the clip
     // bounds based on SaveLayer paints, so the drop shadow could be cut off.
     SkPaint paint;
-    paint.setImageFilter(SkDropShadowImageFilter::Create(20, 0, 0, 0, SK_ColorBLACK))->unref();
+    paint.setImageFilter(SkDropShadowImageFilter::Create(20, 0, 0, 0, SK_ColorBLACK,
+                         SkDropShadowImageFilter::kDrawShadowAndForeground_ShadowMode))->unref();
 
     recorder.saveLayer(NULL, &paint);
         recorder.clipRect(SkRect::MakeWH(20, 40));
         recorder.drawRect(SkRect::MakeWH(20, 40), SkPaint());
     recorder.restore();
 
     // Under the original bug, the right edge value of the drawRect would be 20 less than asserted
     // here because we intersected it with a clip that had not been adjusted for the drop shadow.
     //
     // The second bug showed up as adjusting the picture bounds (0,0,50,50) by the drop shadow too.
@@ skipping 53 matching lines @@
 
     {
         SkRecord record;
         SkRecorder recorder(&record, 10, 10);
         recorder.drawImageRect(image, 0, SkRect::MakeWH(10, 10));
         SkRecordDraw(record, &canvas, 0, 0);
     }
     REPORTER_ASSERT(r, canvas.fDrawImageRectCalled);
 
 }