cc: Add support for partial swaps when using impl-side painting.

cc/trees/damage_tracker_unittest.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/damage_tracker.h"
 
 #include "cc/base/math_util.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/output/filter_operation.h"
 #include "cc/output/filter_operations.h"
@@ skipping 250 matching lines @@
   child->SetUpdateRect(gfx::RectF(20.f, 25.f, 1.f, 2.f));
   EmulateDrawingOneFrame(root.get());
 
   // Damage position on the surface should be: position of update_rect (20, 25)
   // relative to the child (100, 100).
   root_damage_rect =
           root->render_surface()->damage_tracker()->current_damage_rect();
   EXPECT_EQ(gfx::Rect(120, 125, 1, 2).ToString(), root_damage_rect.ToString());
 }
 
+TEST_F(DamageTrackerTest, VerifyDamageForLayerDamageRects) {
+  scoped_ptr<LayerImpl> root = CreateAndSetUpTestTreeWithOneSurface();
+  LayerImpl* child = root->children()[0];
+
+  // CASE 1: Setting the layer damage rect should cause the corresponding damage

[reveman, 2014/04/21 18:48:26]

nit: you're not setting, you're adding a damage rect

+  // to the surface.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(10.f, 11.f, 12.f, 13.f));
+  EmulateDrawingOneFrame(root.get());
+
+  // Damage position on the surface should be: position of layer damage_rect
+  // (10, 11) relative to the child (100, 100).
+  gfx::Rect root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(110, 111, 12, 13).ToString(),
+            root_damage_rect.ToString());

[reveman, 2014/04/21 18:48:26]

nit: as the api is AddDamageRect I think you should only test that the root
damage includes the damage rect and not that it's exactly the same. It being
exactly the same is an implementation detail. Same comment for all the tests
below.

+
+  // CASE 2: The same layer damage rect twice in a row still produces the same
+  // damage.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(10.f, 11.f, 12.f, 13.f));
+  EmulateDrawingOneFrame(root.get());
+  root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(110, 111, 12, 13).ToString(),
+            root_damage_rect.ToString());
+
+  // CASE 3: Setting a different layer damage rect should cause damage on the
+  // new damaged region, but no additional exposed old region.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(20.f, 25.f, 1.f, 2.f));
+  EmulateDrawingOneFrame(root.get());
+
+  // Damage position on the surface should be: position of layer damage_rect
+  // (20, 25) relative to the child (100, 100).
+  root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(120, 125, 1, 2).ToString(), root_damage_rect.ToString());
+}

[reveman, 2014/04/21 18:48:26]

could you include a test where you add more than one damage rect?

+
+TEST_F(DamageTrackerTest, VerifyDamageForLayerUpdateAndDamageRects) {
+  scoped_ptr<LayerImpl> root = CreateAndSetUpTestTreeWithOneSurface();
+  LayerImpl* child = root->children()[0];
+
+  // CASE 1: Setting the layer damage rect and update rect should cause the
+  // corresponding damage to the surface.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(5.f, 6.f, 12.f, 13.f));
+  child->SetUpdateRect(gfx::RectF(15.f, 16.f, 14.f, 10.f));
+  EmulateDrawingOneFrame(root.get());
+
+  // Damage position on the surface should be: position of unified layer
+  // damage_rect and update rect (5, 6)
+  // relative to the child (100, 100).
+  gfx::Rect root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(105, 106, 24, 20).ToString(),
+            root_damage_rect.ToString());
+
+  // CASE 2: The same layer damage rect and update rect twice in a row still
+  // produces the same damage.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(10.f, 11.f, 12.f, 13.f));
+  child->SetUpdateRect(gfx::RectF(10.f, 11.f, 14.f, 15.f));
+  EmulateDrawingOneFrame(root.get());
+  root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(110, 111, 14, 15).ToString(),
+            root_damage_rect.ToString());
+
+  // CASE 3: Setting a different layer damage rect and update rect should cause
+  // damage on the new damaged region, but no additional exposed old region.
+  ClearDamageForAllSurfaces(root.get());
+  child->AddDamageRect(gfx::RectF(20.f, 25.f, 2.f, 3.f));
+  child->SetUpdateRect(gfx::RectF(5.f, 10.f, 7.f, 8.f));
+  EmulateDrawingOneFrame(root.get());
+
+  // Damage position on the surface should be: position of unified layer damage
+  // rect and update rect (5, 10) relative to the child (100, 100).
+  root_damage_rect =
+      root->render_surface()->damage_tracker()->current_damage_rect();
+  EXPECT_EQ(gfx::Rect(105, 110, 17, 18).ToString(),
+            root_damage_rect.ToString());
+}
+
 TEST_F(DamageTrackerTest, VerifyDamageForPropertyChanges) {
   scoped_ptr<LayerImpl> root = CreateAndSetUpTestTreeWithOneSurface();
   LayerImpl* child = root->children()[0];
 
   // CASE 1: The layer's property changed flag takes priority over update rect.
   //
   ClearDamageForAllSurfaces(root.get());
   child->SetUpdateRect(gfx::RectF(10.f, 11.f, 12.f, 13.f));
   child->SetOpacity(0.5f);
   EmulateDrawingOneFrame(root.get());
@@ skipping 1100 matching lines @@
     gfx::Rect root_damage_rect =
         root->render_surface()->damage_tracker()->current_damage_rect();
     gfx::Rect damage_we_care_about = gfx::Rect(i, i);
     EXPECT_LE(damage_we_care_about.right(), root_damage_rect.right());
     EXPECT_LE(damage_we_care_about.bottom(), root_damage_rect.bottom());
   }
 }
 
 }  // namespace
 }  // namespace cc