From f6069db89203f0797e4429c47ae268901c69a299 Mon Sep 17 00:00:00 2001
From: danakj <danakj@chromium.org>
Date: Fri, 12 Sep 2014 17:46:47 -0700
Subject: [PATCH] Propogate the clip rect for visible_content_rect into
 surfaces.

Currently each render surface takes as its clip rect for visible content
rects as the clip rect directly clipping its own surface, but drops the
clip for visible content rects from outside the surface.

This means that the viewport does not clip the visible_content_rect of
any layers that aren't in the root surface. Fixed by intersecting this
clip for visible content rects with the one from outside the surface.

BUG=410625

Review URL: https://codereview.chromium.org/565353002

Cr-Commit-Position: refs/heads/master@{#294706}
---
 cc/trees/layer_tree_host_common.cc          |  7 ++--
 cc/trees/layer_tree_host_common_unittest.cc | 56 +++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/cc/trees/layer_tree_host_common.cc b/cc/trees/layer_tree_host_common.cc
index 840a32b2ef4a..8d2553972591 100644
--- a/cc/trees/layer_tree_host_common.cc
+++ b/cc/trees/layer_tree_host_common.cc
@@ -1945,8 +1945,11 @@ static void CalculateDrawPropertiesInternal(
         // here, or DCHECK that the transform is invertible.
       }
 
+      gfx::Rect surface_clip_rect_in_target_space = gfx::IntersectRects(
+          data_from_ancestor.clip_rect_of_target_surface_in_target_space,
+          ancestor_clip_rect_in_target_space);
       gfx::Rect projected_surface_rect = MathUtil::ProjectEnclosingClippedRect(
-          inverse_surface_draw_transform, ancestor_clip_rect_in_target_space);
+          inverse_surface_draw_transform, surface_clip_rect_in_target_space);
 
       if (layer_draw_properties.num_unclipped_descendants > 0) {
         // If we have unclipped descendants, we cannot count on the render
@@ -2327,7 +2330,7 @@ static void CalculateDrawPropertiesInternal(
     layer->render_target()->render_surface()->
         AddContributingDelegatedRenderPassLayer(layer);
   }
-}
+}  // NOLINT(readability/fn_size)
 
 template <typename LayerType, typename RenderSurfaceLayerListType>
 static void ProcessCalcDrawPropsInputs(
diff --git a/cc/trees/layer_tree_host_common_unittest.cc b/cc/trees/layer_tree_host_common_unittest.cc
index feed1ed02008..0b52e8a2286b 100644
--- a/cc/trees/layer_tree_host_common_unittest.cc
+++ b/cc/trees/layer_tree_host_common_unittest.cc
@@ -8559,5 +8559,61 @@ TEST_F(LayerTreeHostCommonTest, DrawPropertyScales) {
   EXPECT_FLOAT_EQ(4.f, child2_layer->draw_properties().device_scale_factor);
 }
 
+TEST_F(LayerTreeHostCommonTest, VisibleContentRectInChildRenderSurface) {
+  scoped_refptr<Layer> root = Layer::Create();
+  SetLayerPropertiesForTesting(root.get(),
+                               gfx::Transform(),
+                               gfx::Point3F(),
+                               gfx::PointF(),
+                               gfx::Size(768 / 2, 3000),
+                               true,
+                               false);
+  root->SetIsDrawable(true);
+
+  scoped_refptr<Layer> clip = Layer::Create();
+  SetLayerPropertiesForTesting(clip.get(),
+                               gfx::Transform(),
+                               gfx::Point3F(),
+                               gfx::PointF(),
+                               gfx::Size(768 / 2, 10000),
+                               true,
+                               false);
+  clip->SetMasksToBounds(true);
+
+  scoped_refptr<Layer> content = Layer::Create();
+  SetLayerPropertiesForTesting(content.get(),
+                               gfx::Transform(),
+                               gfx::Point3F(),
+                               gfx::PointF(),
+                               gfx::Size(768 / 2, 10000),
+                               true,
+                               false);
+  content->SetIsDrawable(true);
+  content->SetForceRenderSurface(true);
+
+  root->AddChild(clip);
+  clip->AddChild(content);
+
+  scoped_ptr<FakeLayerTreeHost> host = FakeLayerTreeHost::Create();
+  host->SetRootLayer(root);
+
+  gfx::Size device_viewport_size(768, 582);
+  RenderSurfaceLayerList render_surface_layer_list;
+  LayerTreeHostCommon::CalcDrawPropsMainInputsForTesting inputs(
+      host->root_layer(), device_viewport_size, &render_surface_layer_list);
+  inputs.device_scale_factor = 2.f;
+  inputs.page_scale_factor = 1.f;
+  inputs.page_scale_application_layer = NULL;
+  LayerTreeHostCommon::CalculateDrawProperties(&inputs);
+
+  // Layers in the root render surface have their visible content rect clipped
+  // by the viewport.
+  EXPECT_EQ(gfx::Rect(768 / 2, 582 / 2), root->visible_content_rect());
+
+  // Layers drawing to a child render surface should still have their visible
+  // content rect clipped by the viewport.
+  EXPECT_EQ(gfx::Rect(768 / 2, 582 / 2), content->visible_content_rect());
+}
+
 }  // namespace
 }  // namespace cc
-- 
2.11.4.GIT