Use SkSrc_Mode in SkCanvasVideoRenderer, to prevent transparent video frames from blending with reu…

media/filters/skcanvas_video_renderer_unittest.cc

Index: media/filters/skcanvas_video_renderer_unittest.cc
diff --git a/media/filters/skcanvas_video_renderer_unittest.cc b/media/filters/skcanvas_video_renderer_unittest.cc
index dd01c704968b2b33c7f3114972d2702ee93b098f..5db3a34d6cfa260029c62ddd8b4c1ba5b56a8875 100644
--- a/media/filters/skcanvas_video_renderer_unittest.cc
+++ b/media/filters/skcanvas_video_renderer_unittest.cc
@@ -214,6 +214,16 @@ TEST_F(SkCanvasVideoRendererTest, NoFrame) {
   EXPECT_EQ(SK_ColorBLACK, GetColor(target_canvas()));
 }
 
+TEST_F(SkCanvasVideoRendererTest, TransparentFrame) {
+  // Test that we don't blend with existing canvas contents.
+  FillCanvas(target_canvas(), SK_ColorRED);
+  Paint(VideoFrame::CreateTransparentFrame(gfx::Size(kWidth, kHeight)),
+        target_canvas(),
+        kNone);
+  EXPECT_EQ(static_cast<SkColor>(SK_ColorTRANSPARENT),
+            GetColor(target_canvas()));
+}
+
 TEST_F(SkCanvasVideoRendererTest, Natural) {
   Paint(natural_frame(), target_canvas(), kRed);
   EXPECT_EQ(SK_ColorRED, GetColor(target_canvas()));