Avoid passing uninitialized value to markRectAsNonOpaque.

Source/platform/graphics/GraphicsContextTest.cpp

Index: Source/platform/graphics/GraphicsContextTest.cpp
diff --git a/Source/platform/graphics/GraphicsContextTest.cpp b/Source/platform/graphics/GraphicsContextTest.cpp
index fd4a9588621b018e68224fc9756d57c97ef4e61d..a117f0b92b4bc574bc0bb740b30960590b8bfcd0 100644
--- a/Source/platform/graphics/GraphicsContextTest.cpp
+++ b/Source/platform/graphics/GraphicsContextTest.cpp
@@ -1042,6 +1042,85 @@ TEST(GraphicsContextTest, PreserveOpaqueOnlyMattersForFirstLayer)
     EXPECT_PIXELS_MATCH_EXACT(bitmap, context.opaqueRegion().asRect());
 }
 
+TEST(GraphicsContextTest, OpaqueRegionForLayerWithNonRectDeviceClip)
+{
+    SkBitmap bitmap;
+    ASSERT_TRUE(bitmap.allocN32Pixels(100, 100));
+    bitmap.eraseColor(0);
+    SkCanvas canvas(bitmap);
+
+    GraphicsContext context(&canvas);
+    context.setRegionTrackingMode(GraphicsContext::RegionTrackingOpaque);
+    Color opaque(1.0f, 0.0f, 0.0f, 1.0f);
+
+    context.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);
+
+    context.setCompositeOperation(CompositeSourceOver);
+    context.beginTransparencyLayer(0.5);
+

[danakj, 2014/08/07 12:49:55]

nit: rm extra whitespace here

[sohanjg, 2014/08/07 14:05:20]

Done.

+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(30, 30, 70, 70), context.opaqueRegion().asRect());
+
+    Path path;
+    path.moveTo(FloatPoint(0, 0));
+    path.addLineTo(FloatPoint(50, 50));
+
+    // For opaque preserving mode and deviceClip is not rect
+    // we will not alter opaque rect.
+    context.clipPath(path, RULE_EVENODD);
+
+    context.setCompositeOperation(CompositeSourceOver);
+    context.beginTransparencyLayer(0.5);
+

[danakj, 2014/08/07 12:49:55]

nit: rm extra whitespace here

[sohanjg, 2014/08/07 14:05:20]

Done.

+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(30, 30, 70, 70), context.opaqueRegion().asRect());
+
+    // For non-opaque preserving mode and deviceClip is not rect
+    // we will mark opaque rect as empty.
+    context.setCompositeOperation(CompositeSourceOut);
+    context.beginTransparencyLayer(0.5);
+
+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(), context.opaqueRegion().asRect());
+}
+
+TEST(GraphicsContextTest, OpaqueRegionForLayerWithRectDeviceClip)
+{
+
+    SkBitmap bitmap;
+    ASSERT_TRUE(bitmap.allocN32Pixels(100, 100));
+    bitmap.eraseColor(0);
+    SkCanvas canvas(bitmap);
+
+    Color opaque(1.0f, 0.0f, 0.0f, 1.0f);
+
+    GraphicsContext context(&canvas);
+    context.setRegionTrackingMode(GraphicsContext::RegionTrackingOpaque);
+
+    context.fillRect(FloatRect(30, 30, 90, 90), opaque, CompositeSourceOver);
+    EXPECT_EQ_RECT(IntRect(30, 30, 70, 70), context.opaqueRegion().asRect());
+
+    // For non-opaque preserving mode and deviceClip is rect
+    // we will mark device clip rect as non opaque.
+    context.setCompositeOperation(CompositeSourceOut);
+    context.beginTransparencyLayer(0.5);
+

[danakj, 2014/08/07 12:49:55]

nit: rm extra whitespace here 

[sohanjg, 2014/08/07 14:05:20]

Done.

+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(), context.opaqueRegion().asRect());
+    EXPECT_PIXELS_MATCH(bitmap, context.opaqueRegion().asRect());
+
+    context.fillRect(FloatRect(30, 30, 100, 100), opaque, CompositeSourceOver);
+
+    // For opaque preserving mode and deviceClip is rect
+    // we will intersect device clip rect with src opaque rect.

[danakj, 2014/08/07 12:49:56]

You didn't set any device clip rect in this test, can you set one so we see this
intersection happening?

[sohanjg, 2014/08/07 14:05:20]

Done.

+    context.setCompositeOperation(CompositeSourceOver);
+    context.beginTransparencyLayer(0.5);
+

[danakj, 2014/08/07 12:49:55]

nit: rm extra whitespace here

[sohanjg, 2014/08/07 14:05:20]

Done.

+    context.endLayer();
+    EXPECT_EQ_RECT(IntRect(30, 30, 70, 70), context.opaqueRegion().asRect());
+    EXPECT_PIXELS_MATCH(bitmap, context.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);