Make RTree handle the case where the playback canvas has empty clip bounds

tests/PictureTest.cpp

Index: tests/PictureTest.cpp
diff --git a/tests/PictureTest.cpp b/tests/PictureTest.cpp
index fa4dc101421da570449bbeba487624365bf5a091..85dbe65cfa0daf427f47949ea1ad226e22dea570 100644
--- a/tests/PictureTest.cpp
+++ b/tests/PictureTest.cpp
@@ -1535,6 +1535,56 @@ static void test_draw_empty(skiatest::Reporter* reporter) {
     }
 }
 
+static void test_draw_empty_clip(skiatest::Reporter* reporter) {
+    SkBitmap result;
+    make_bm(&result, 2, 2, SK_ColorGREEN, false);
+
+    // Test playing a non-empty picture into a canvas with an empty clip
+    SkCanvas destinationCanvas(result);
+    destinationCanvas.clipRect(SkRect::MakeXYWH(10, 10, 1, 1), SkRegion::kIntersect_Op);
+    SkPaint paint;
+
+    {
+        // stock SkPicture
+        SkPictureRecorder recorder;
+        SkCanvas* canvas = recorder.beginRecording(3, 3);

[reed1, 2014/10/28 17:39:51]

we seem to make this picture three times, but only wi/ diff opts to the "begin"
method. Can we refactor this to not have so much copy/paste? It might also make
it easy to later extend for other bbox options (or diff picture content).

+        canvas->drawRect(SkRect::MakeXYWH(0, 0, 3, 3), paint);
+        SkAutoTUnref<SkPicture> picture(recorder.endRecording());
+
+        destinationCanvas.drawPicture(picture);
+        REPORTER_ASSERT(reporter, SK_ColorGREEN == result.getColor(0, 0));
+    }
+
+    {
+        // tile grid
+        SkTileGridFactory::TileGridInfo gridInfo;
+        gridInfo.fMargin.setEmpty();
+        gridInfo.fOffset.setZero();
+        gridInfo.fTileInterval.set(1, 1);
+
+        SkTileGridFactory factory(gridInfo);
+        SkPictureRecorder recorder;
+        SkCanvas* canvas = recorder.beginRecording(3, 3, &factory);
+        canvas->drawRect(SkRect::MakeXYWH(0, 0, 3, 3), paint);
+        SkAutoTUnref<SkPicture> picture(recorder.endRecording());
+
+        destinationCanvas.drawPicture(picture);
+        REPORTER_ASSERT(reporter, SK_ColorGREEN == result.getColor(0, 0));
+    }
+
+    {
+        // RTree
+        SkRTreeFactory factory;
+        SkPictureRecorder recorder;
+        SkCanvas* canvas = recorder.beginRecording(3, 3, &factory);
+        canvas->drawRect(SkRect::MakeXYWH(0, 0, 3, 3), paint);
+        SkAutoTUnref<SkPicture> picture(recorder.endRecording());
+
+        destinationCanvas.drawPicture(picture);
+        REPORTER_ASSERT(reporter, SK_ColorGREEN == result.getColor(0, 0));
+    }
+}
+
 static void test_clip_bound_opt(skiatest::Reporter* reporter) {
     // Test for crbug.com/229011
     SkRect rect1 = SkRect::MakeXYWH(SkIntToScalar(4), SkIntToScalar(4),
@@ -1766,6 +1816,7 @@ DEF_TEST(Picture, reporter) {
     test_gatherpixelrefsandrects(reporter);
     test_bitmap_with_encoded_data(reporter);
     test_draw_empty(reporter);
+    test_draw_empty_clip(reporter);
     test_clip_bound_opt(reporter);
     test_clip_expansion(reporter);
     test_hierarchical(reporter);