Avoid passing uninitialized value to markRectAsNonOpaque.

Source/platform/graphics/GraphicsContextTest.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 1024 matching lines @@
     context.setFillColor(opaque);
     path.moveTo(FloatPoint(10, 10));
     path.addLineTo(FloatPoint(40, 40));
     context.strokePath(path);
 
     context.endLayer();
     EXPECT_EQ_RECT(IntRect(), context.opaqueRegion().asRect());
     EXPECT_PIXELS_MATCH_EXACT(bitmap, context.opaqueRegion().asRect());
 }
 
+TEST(GraphicsContextTest, OpaqueRegionForLayer)
+{
+    // For non-opaque preserving mode and deviceClip is not rect
+    // we will mark opaque rect as empty.
+    Path path;
+    path.moveTo(FloatPoint(0, 0));
+    path.addLineTo(FloatPoint(50, 50));
+
+    SkCanvas canvas(400, 400);
+    GraphicsContext context(&canvas);
+    context.clipPath(path, RULE_EVENODD);
+    context.setRegionTrackingMode(GraphicsContext::RegionTrackingOpaque);
+
+    Color opaque(1.0f, 0.0f, 0.0f, 1.0f);
+
+    context.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);

[danakj, 2014/08/05 15:26:54]

Can you EXPECT_EQ the opaqueRegion after this, and verify it's not empty so we
see the code below actually doing something?

[sohanjg, 2014/08/06 05:56:21]

Done.

+    context.setCompositeOperation(CompositeSourceOut);
+    context.beginTransparencyLayer(0.5);
+
+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(), context.opaqueRegion().asRect());
+
+    // For opaque preserving mode and deviceClip is not rect
+    // we will not alter opaque rect.
+    context.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);
+    context.setCompositeOperation(CompositeSourceOver);
+    context.beginTransparencyLayer(0.5);
+
+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(), context.opaqueRegion().asRect());
+
+    SkBitmap bitmap;
+    ASSERT_TRUE(bitmap.allocN32Pixels(400, 400));
+    bitmap.eraseColor(0);
+    SkCanvas canvas2(bitmap);
+
+    GraphicsContext context2(&canvas2);
+    context2.setRegionTrackingMode(GraphicsContext::RegionTrackingOpaque);
+
+    // For non-opaque preserving mode and deviceClip is rect
+    // we will mark device clip rect as non opaque.
+    context2.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);

[danakj, 2014/08/05 15:26:54]

Can you EXPECT_EQ the opaqueRegion after this, and verify it's not empty so we
see the code below actually doing something?

Also how does this part differ from the above other than using a bitmap? Do we
need both or is just this one enough?

[sohanjg, 2014/08/05 16:48:12]

this part has device clip as 'rect', we would need to test that too, right ? or
it can be ignored ?

[danakj, 2014/08/05 17:18:34]

Oh, this is a different context, i missed that "2". Can you split this into a
separate test case?

[sohanjg, 2014/08/06 05:56:21]

Done.

+    context2.setCompositeOperation(CompositeSourceOut);
+    context2.beginTransparencyLayer(0.5);
+
+    context2.endLayer();
+    EXPECT_EQ_RECT(IntRect(), context2.opaqueRegion().asRect());
+    EXPECT_PIXELS_MATCH(bitmap, context2.opaqueRegion().asRect());
+
+    // For opaque preserving mode and deviceClip is rect
+    // we will intersect device clip rect with src opaque rect.
+    context2.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);
+    context2.setCompositeOperation(CompositeSourceOver);
+    context2.beginTransparencyLayer(0.5);
+
+    context2.endLayer();
+    EXPECT_EQ_RECT(IntRect(30, 30, 90, 90), context2.opaqueRegion().asRect());
+    EXPECT_PIXELS_MATCH(bitmap, context2.opaqueRegion().asRect());
+}
+
 #define DISPATCH1(c1, c2, op, param1) do { c1.op(param1); c2.op(param1); } while (0);
 #define DISPATCH2(c1, c2, op, param1, param2) do { c1.op(param1, param2); c2.op(param1, param2); } while (0);
 
 TEST(GraphicsContextTest, RecordingTotalMatrix)
 {
     SkBitmap bitmap;
     ASSERT_TRUE(bitmap.allocN32Pixels(400, 400));
     bitmap.eraseColor(0);
     SkCanvas canvas(bitmap);
     GraphicsContext context(&canvas);
@@ skipping 59 matching lines @@
     EXPECT_FALSE(pic);
 
     // endRecording finally makes the picture accessible
     dl->endRecording();
     pic = dl->picture();
     EXPECT_TRUE(pic);
     EXPECT_EQ(1, pic->getRefCnt());
 }
 
 } // namespace