Make sure pictures draw Clears even when the clip is empty.

tests/PictureBBHTest.cpp

Index: tests/PictureBBHTest.cpp
diff --git a/tests/PictureBBHTest.cpp b/tests/PictureBBHTest.cpp
index 3ff5625686b298fdcd99357222d1b9daa066ab9c..2caa4b3886b4543048b264f91c91db4fbf4c0bb3 100644
--- a/tests/PictureBBHTest.cpp
+++ b/tests/PictureBBHTest.cpp
@@ -49,7 +49,9 @@ private:
         SkCanvas playbackCanvas(fResultBitmap);
         playbackCanvas.clear(SK_ColorGREEN);
         SkPictureRecorder recorder;
-        SkCanvas* recordCanvas = recorder.beginRecording(SkIntToScalar(fPictureWidth), SkIntToScalar(fPictureHeight), factory);
+        SkCanvas* recordCanvas = recorder.beginRecording(SkIntToScalar(fPictureWidth),
+                                                         SkIntToScalar(fPictureHeight),
+                                                         factory);
         this->doTest(playbackCanvas, *recordCanvas);
         SkAutoTUnref<SkPicture> picture(recorder.endRecording());
         playbackCanvas.drawPicture(picture);
@@ -99,3 +101,37 @@ DEF_TEST(PictureBBH, reporter) {
     EmptyClipPictureBBHTest emptyClipPictureTest;
     emptyClipPictureTest.run(reporter);
 }
+
+static void test_clear(skiatest::Reporter* r, SkBBHFactory* factory) {
+    // Make a single red pixel.
+    SkBitmap bm;
+    bm.allocN32Pixels(1,1);
+    SkCanvas dst(bm);
+    dst.clear(SK_ColorRED);
+
+    // Clip our canvas down to empty.
+    dst.clipRect(SkRect::MakeWH(0,0));
+
+    // clear() should still set that pixel to true, because it ignores the clip.
+    dst.clear(SK_ColorBLUE);
+    REPORTER_ASSERT(r, SK_ColorBLUE == bm.getColor(0,0));
+
+    // Should also work if we do the draw via an SkPicture.
+    SkPictureRecorder rec;
+    SkCanvas* src = rec.beginRecording(1,1, factory);
+        src->clear(SK_ColorGREEN);
+    SkAutoTDelete<SkPicture> pic(rec.endRecording());
+    pic->playback(&dst);
+    REPORTER_ASSERT(r, SK_ColorGREEN == bm.getColor(0,0));
+}
+
+DEF_TEST(PictureBBH_Clear, r) {
+    test_clear(r, NULL);
+
+    SkTileGridFactory::TileGridInfo grid = { {1,1}, {0,0}, {0,0} };
+    SkTileGridFactory tilegrid(grid);
+    test_clear(r, &tilegrid);
+
+    SkRTreeFactory rtree;
+    test_clear(r, &rtree);
+}