Adds a bounds parameter to ui::Compositor::ReadPixels

ui/gfx/compositor/layer_unittest.cc

Index: ui/gfx/compositor/layer_unittest.cc
diff --git a/ui/gfx/compositor/layer_unittest.cc b/ui/gfx/compositor/layer_unittest.cc
index aa16ceb94be5cac90380c21c9715ca8924ca3def..91bbc6438d96e453f226170e7a6891565819c32f 100644
--- a/ui/gfx/compositor/layer_unittest.cc
+++ b/ui/gfx/compositor/layer_unittest.cc
@@ -1007,16 +1007,24 @@ TEST_F(LayerWithNullDelegateTest, SetBoundsSchedulesPaint) {
 TEST_F(LayerWithRealCompositorTest, MAYBE_DrawPixels) {
   scoped_ptr<Layer> layer(CreateColorLayer(SK_ColorRED,
                                            gfx::Rect(0, 0, 500, 500)));
+  scoped_ptr<Layer> layer2(CreateColorLayer(SK_ColorBLUE,
+                                            gfx::Rect(0, 0, 500, 10)));
+
+  layer->Add(layer2.get());
+
   DrawTree(layer.get());
 
   SkBitmap bitmap;
-  ASSERT_TRUE(GetCompositor()->ReadPixels(&bitmap));
+  gfx::Size size = GetCompositor()->size();
+  ASSERT_TRUE(GetCompositor()->ReadPixels(&bitmap,
+                                          gfx::Rect(0, 10,
+                                          size.width(), size.height() - 10)));
   ASSERT_FALSE(bitmap.empty());
 
   SkAutoLockPixels lock(bitmap);
   bool is_all_red = true;
   for (int x = 0; is_all_red && x < 500; x++)
-    for (int y = 0; is_all_red && y < 500; y++)
+    for (int y = 0; is_all_red && y < 490; y++)
       is_all_red = is_all_red && (bitmap.getColor(x, y) == SK_ColorRED);
 
   EXPECT_TRUE(is_all_red);