Dirty rects always contain full tiles with delegated rendering.

cc/trees/layer_tree_host_unittest_damage.cc

Index: cc/trees/layer_tree_host_unittest_damage.cc
diff --git a/cc/trees/layer_tree_host_unittest_damage.cc b/cc/trees/layer_tree_host_unittest_damage.cc
index 58644e63b50e1c077d8f794ff39e2b54ac9645cd..dc6c22a39fdbee45e3dec78d3da3991a46007b7d 100644
--- a/cc/trees/layer_tree_host_unittest_damage.cc
+++ b/cc/trees/layer_tree_host_unittest_damage.cc
@@ -372,9 +372,21 @@ class LayerTreeHostDamageTestForcedFullDamage : public LayerTreeHostDamageTest {
         } else {
           // When using a delegating renderer, or using impl side painting, the
           // entire child is considered damaged as we need to replace its
-          // resources with newly created ones.
-          EXPECT_EQ(gfx::RectF(child_->position(), child_->bounds()).ToString(),
+          // resources with newly created ones. The damaged area is kept as it
+          // is, but entire child is painted.
+
+          // Verify damage area.

[danakj, 2013/12/02 15:09:49]

Instead of saying "Verify damage area" which is clear that's what you're doing,
you can say why you expect the damage area to be, or why. ie. "The damaged area
should match the invalidation exactly.

It looks like you could move the root_damage check out of this if/else statement
entirely, since it'll always be the same now. And just test the paint_rect in
the if/else (also add an if case to demonstrate the difference?)

+          EXPECT_EQ(gfx::RectF(100+10, 100+11, 12, 13).ToString(),
                     root_damage.ToString());
+          // Verify paint area.

[danakj, 2013/12/02 15:09:49]

Same here, say what you're expecting or why rather than just stating that you're
verifying something.

+          gfx::RectF paint_rect = static_cast<gfx::RectF>

[danakj, 2013/12/02 15:06:52]

You don't need to cast from Rect to RectF

+                                  (child_->Updater()->content_rect());
+          EXPECT_EQ((gfx::RectF(child_->bounds()).ToString()),

[danakj, 2013/12/02 15:06:52]

you don't need () around the RectF.ToString() call

+                    paint_rect.ToString());

[prashant.n, 2013/12/02 14:30:48]

Do we need this as we can verify with actual values?

+          paint_rect.set_origin(child_->position());
+          EXPECT_EQ(gfx::RectF(100, 100, 30, 30).ToString(),
+                    paint_rect.ToString());
+          EXPECT_FALSE(root_damage.Contains(paint_rect));

[prashant.n, 2013/12/02 14:30:48]

Should we verify this, as we have verified with actual values?
(100+10, 100+11, 12, 13) is inside (100, 100, 30, 30).

[danakj, 2013/12/02 15:06:52]

I think the above check against layer->bounds() is enough.

         }
         EXPECT_FALSE(frame_data->has_no_damage);