ui: Clean up damaged rects and clear them after painting.

This cleans up some of the damage rects code by converting the SkRegion
to a cc::Region, allowing use of gfx::Rects. It moves the recursion
over the Layer tree out to Compositor instead of on Layer.

And we keep the damaged_region_ valid until the layer is painted. This
will allow us to pass that damaged_region_ to the painting code with
impl-side slimming paint, because with impl-side painting, the paint
clip rect can be larger than the invalidations (as large as the whole
layer).

R=piman@chromium.org, sky
BUG=466426

Committed: https://crrev.com/a5e585868e16ce53c990f764d4943592f11749aa
Cr-Commit-Position: refs/heads/master@{#326547}

Review URL: https://codereview.chromium.org/1080633009

Cr-Commit-Position: refs/heads/master@{#326912}

4 files changed, 44 insertions, 41 deletions

diff --git a/content/browser/compositor/reflector_impl_unittest.cc b/content/browser/compositor/reflector_impl_unittest.cc
index 2f0c299..867a9de 100644
--- a/content/browser/compositor/reflector_impl_unittest.cc
+++ b/content/browser/compositor/reflector_impl_unittest.cc
@@ -91,8 +91,7 @@ class TestOutputSurface : public BrowserCompositorOutputSurface {
   gfx::Size SurfaceSize() const override { return gfx::Size(256, 256); }
 };
 
-const gfx::Rect kSubRect = gfx::Rect(0, 0, 64, 64);
-const SkIRect kSkSubRect = SkIRect::MakeXYWH(0, 0, 64, 64);
+const gfx::Rect kSubRect(0, 0, 64, 64);
 
 }  // namespace
 
@@ -161,10 +160,10 @@ TEST_F(ReflectorImplTest, CheckNormalOutputSurface) {
   SetUpReflector();
   UpdateTexture();
   EXPECT_TRUE(mirroring_layer_->TextureFlipped());
-  EXPECT_EQ(SkRegion(SkIRect::MakeXYWH(
-                0, output_surface_->SurfaceSize().height() - kSubRect.height(),
-                kSubRect.width(), kSubRect.height())),
-            mirroring_layer_->damaged_region());
+  gfx::Rect expected_rect =
+      kSubRect + gfx::Vector2d(0, output_surface_->SurfaceSize().height()) -
+      gfx::Vector2d(0, kSubRect.height());
+  EXPECT_EQ(expected_rect, mirroring_layer_->damaged_region());
 }
 
 TEST_F(ReflectorImplTest, CheckInvertedOutputSurface) {
@@ -172,7 +171,7 @@ TEST_F(ReflectorImplTest, CheckInvertedOutputSurface) {
   SetUpReflector();
   UpdateTexture();
   EXPECT_FALSE(mirroring_layer_->TextureFlipped());
-  EXPECT_EQ(SkRegion(kSkSubRect), mirroring_layer_->damaged_region());
+  EXPECT_EQ(kSubRect, mirroring_layer_->damaged_region());
 }
 
 #if defined(USE_OZONE)
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 43dd460..c50f9ef 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -326,9 +326,16 @@ void Compositor::BeginMainFrame(const cc::BeginFrameArgs& args) {
 void Compositor::BeginMainFrameNotExpectedSoon() {
 }
 
+static void SendDamagedRectsRecursive(ui::Layer* layer) {
+  layer->SendDamagedRects();
+  for (auto* child : layer->children())
+    SendDamagedRectsRecursive(child);
+}
+
 void Compositor::Layout() {
-  if (root_layer_)
-    root_layer_->SendDamagedRects();
+  if (!root_layer())
+    return;
+  SendDamagedRectsRecursive(root_layer());
 }
 
 void Compositor::RequestNewOutputSurface() {
diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index 3e61d40..914e000 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -657,11 +657,7 @@ bool Layer::SchedulePaint(const gfx::Rect& invalid_rect) {
       type_ == LAYER_NINE_PATCH || (!delegate_ && !mailbox_.IsValid()))
     return false;
 
-  damaged_region_.op(invalid_rect.x(),
-                     invalid_rect.y(),
-                     invalid_rect.right(),
-                     invalid_rect.bottom(),
-                     SkRegion::kUnion_Op);
+  damaged_region_.Union(invalid_rect);
   ScheduleDraw();
   return true;
 }
@@ -673,20 +669,17 @@ void Layer::ScheduleDraw() {
 }
 
 void Layer::SendDamagedRects() {
-  if ((delegate_ || mailbox_.IsValid()) && !damaged_region_.isEmpty()) {
-    for (SkRegion::Iterator iter(damaged_region_); !iter.done(); iter.next()) {
-      const SkIRect& sk_damaged = iter.rect();
-      gfx::Rect damaged(
-          sk_damaged.x(),
-          sk_damaged.y(),
-          sk_damaged.width(),
-          sk_damaged.height());
-      cc_layer_->SetNeedsDisplayRect(damaged);
-    }
-    damaged_region_.setEmpty();
-  }
-  for (size_t i = 0; i < children_.size(); ++i)
-    children_[i]->SendDamagedRects();
+  if (damaged_region_.IsEmpty())
+    return;
+  if (!delegate_ && !mailbox_.IsValid())
+    return;
+
+  for (cc::Region::Iterator iter(damaged_region_); iter.has_rect(); iter.next())
+    cc_layer_->SetNeedsDisplayRect(iter.rect());
+}
+
+void Layer::ClearDamagedRects() {
+  damaged_region_.Clear();
 }
 
 void Layer::CompleteAllAnimations() {
@@ -745,6 +738,7 @@ void Layer::PaintContents(
     const gfx::Rect& clip,
     ContentLayerClient::PaintingControlSetting painting_control) {
   TRACE_EVENT1("ui", "Layer::PaintContents", "name", name_);
+  ClearDamagedRects();
   scoped_ptr<gfx::Canvas> canvas(gfx::Canvas::CreateCanvasWithoutScaling(
       sk_canvas, device_scale_factor_));
   if (delegate_)
@@ -756,15 +750,16 @@ void Layer::PaintContentsToDisplayList(
     const gfx::Rect& clip,
     ContentLayerClient::PaintingControlSetting painting_control) {
   TRACE_EVENT1("ui", "Layer::PaintContentsToDisplayList", "name", name_);
-  if (delegate_) {
-    // TODO(danakj): Save the invalidation on the layer and pass that down
-    // instead of the |clip| here. That will break everything until View
-    // early-outs emit cached display items instead of nothing.
-    gfx::Rect invalidation = clip;
-    DCHECK(clip.Contains(invalidation));
-    delegate_->OnPaintLayer(
-        PaintContext(display_list, device_scale_factor_, clip, invalidation));
-  }
+  ClearDamagedRects();
+  if (!delegate_)
+    return;
+  // TODO(danakj): Save the invalidation on the layer and pass that down
+  // instead of the |clip| here. That will break everything until View
+  // early-outs emit cached display items instead of nothing.
+  gfx::Rect invalidation = clip;
+  DCHECK(clip.Contains(invalidation));
+  delegate_->OnPaintLayer(
+      PaintContext(display_list, device_scale_factor_, clip, invalidation));
 }
 
 bool Layer::FillsBoundsCompletely() const { return fills_bounds_completely_; }
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index 381e982..bb8b1af 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -14,6 +14,7 @@
 #include "base/message_loop/message_loop.h"
 #include "cc/animation/animation_events.h"
 #include "cc/animation/layer_animation_event_observer.h"
+#include "cc/base/region.h"
 #include "cc/base/scoped_ptr_vector.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/layer_client.h"
@@ -319,8 +320,9 @@ class COMPOSITOR_EXPORT Layer
   // Uses damaged rectangles recorded in |damaged_region_| to invalidate the
   // |cc_layer_|.
   void SendDamagedRects();
+  void ClearDamagedRects();
 
-  const SkRegion& damaged_region() const { return damaged_region_; }
+  const cc::Region& damaged_region() const { return damaged_region_; }
 
   void CompleteAllAnimations();
 
@@ -459,9 +461,9 @@ class COMPOSITOR_EXPORT Layer
   bool fills_bounds_opaquely_;
   bool fills_bounds_completely_;
 
-  // Union of damaged rects, in pixel coordinates, to be used when
-  // compositor is ready to paint the content.
-  SkRegion damaged_region_;
+  // Union of damaged rects, in layer space, to be used when compositor is ready
+  // to paint the content.
+  cc::Region damaged_region_;
 
   int background_blur_radius_;