Fixes transform of holes to match that of the child view in ::Draw

The transform applied to holes was incorrect when the bounds of the child were non zero
In Layer::Draw the transform is first applied, then the translation, changed the code in Layer::RecomputeHole to match that

This put the holes in the wrong place for the views_desktop demo.

I have not seen a place where this was broken in chromium, however it might prevent
future bugs once we apply transformations to child views

BUG=None
TEST=None

Review URL: http://codereview.chromium.org/8249005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@105340 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 18 insertions, 8 deletions

diff --git a/ui/gfx/compositor/layer.cc b/ui/gfx/compositor/layer.cc
index b9b1cd3..8266bff 100644
--- a/ui/gfx/compositor/layer.cc
+++ b/ui/gfx/compositor/layer.cc
@@ -328,8 +328,15 @@ void Layer::RecomputeHole() {
         !IsApproximateMultilpleOf(degrees, 90.0f))
       continue;
 
-    gfx::Rect candidate_hole = children_[i]->bounds();
-    children_[i]->transform().TransformRect(&candidate_hole);
+    // The reason why we don't just take the bounds and apply the transform is
+    // that the bounds encodes a position, too, so the effective transformation
+    // matrix is actually different that the one reported. As well, the bounds
+    // will not necessarily be at the origin.
+    gfx::Rect candidate_hole(children_[i]->bounds_.size());
+    ui::Transform transform = children_[i]->transform();
+    transform.ConcatTranslate(static_cast<float>(children_[i]->bounds_.x()),
+                              static_cast<float>(children_[i]->bounds_.y()));
+    transform.TransformRect(&candidate_hole);
 
     // This layer might not contain the child (e.g., a portion of the child may
     // be offscreen). Only the portion of the child that overlaps this layer is
diff --git a/ui/gfx/compositor/layer_unittest.cc b/ui/gfx/compositor/layer_unittest.cc
index 5521cf2..bb05c0b 100644
--- a/ui/gfx/compositor/layer_unittest.cc
+++ b/ui/gfx/compositor/layer_unittest.cc
@@ -539,9 +539,9 @@ TEST_F(LayerWithNullDelegateTest, NoHoleWithTransform) {
   EXPECT_TRUE(!parent->hole_rect().IsEmpty());
 
   ui::Transform t;
-  t.SetTranslate(-75, -75);
+  t.SetTranslate(-50, -50);
   t.ConcatRotate(45.0f);
-  t.ConcatTranslate(75, 75);
+  t.ConcatTranslate(50, 50);
   child->SetTransform(t);
 
   EXPECT_EQ(gfx::Rect(0, 0, 0, 0), parent->hole_rect());
@@ -558,13 +558,16 @@ TEST_F(LayerWithNullDelegateTest, HoleWithNinetyDegreeTransforms) {
 
   for (int i = -4; i <= 4; ++i) {
     ui::Transform t;
-    t.SetTranslate(-75, -75);
+    // Need to rotate in local coordinates.
+    t.SetTranslate(-25, -25);
     t.ConcatRotate(90.0f * i);
-    t.ConcatTranslate(75, 75);
+    t.ConcatTranslate(25, 25);
     child->SetTransform(t);
 
-    gfx::Rect target_rect = child->bounds();
-    child->transform().TransformRect(&target_rect);
+    gfx::Rect target_rect(child->bounds().size());
+    t.ConcatTranslate(child->bounds().x(), child->bounds().y());
+    t.TransformRect(&target_rect);
+
     EXPECT_EQ(target_rect, parent->hole_rect());
   }
 }