optimization/fix: dirty the clip-bounds when we mod the clip in savelayer

tests/QuickRejectTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkDrawLooper.h"
 #include "SkTypes.h"
@@ skipping 69 matching lines @@
 
     // now install our looper, which will draw, since it internally translates
     // to the left. The test is to ensure that canvas' quickReject machinary
     // allows us through, even though sans-looper we would look like we should
     // be clipped out.
     paint.setLooper(new TestLooper)->unref();
     canvas.drawBitmap(src, SkIntToScalar(-10), 0, &paint);
     REPORTER_ASSERT(reporter, 0xFFFFFFFF == *dst.getAddr32(5, 5));
 }
 
+static void test_layers(skiatest::Reporter* reporter) {
+    SkCanvas canvas(100, 100);
+
+    SkRect r = SkRect::MakeWH(10, 10);
+    REPORTER_ASSERT(reporter, false == canvas.quickReject(r));
+
+    r.offset(300, 300);
+    REPORTER_ASSERT(reporter, true == canvas.quickReject(r));
+
+    // Test that saveLayer updates quickReject
+    SkRect bounds = SkRect::MakeLTRB(50, 50, 70, 70);
+    canvas.saveLayer(&bounds, NULL);
+    REPORTER_ASSERT(reporter, true == canvas.quickReject(SkRect::MakeWH(10, 10)));
+    REPORTER_ASSERT(reporter, false == canvas.quickReject(SkRect::MakeWH(60, 60)));
+}
+
 DEF_TEST(QuickReject, reporter) {
     test_drawBitmap(reporter);
+    test_layers(reporter);
 }