Use SkRegion (set of rectangles) to record damaged rects

instead of unifying them into single rect.

BUG=none
TEST=non

Review URL: http://codereview.chromium.org/9609020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@125125 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 29 insertions, 21 deletions

diff --git a/ui/gfx/compositor/compositor.cc b/ui/gfx/compositor/compositor.cc
index 506b0ca..5f429ba03 100644
--- a/ui/gfx/compositor/compositor.cc
+++ b/ui/gfx/compositor/compositor.cc
@@ -264,7 +264,7 @@ void Compositor::updateAnimations(double frameBeginTime) {
 
 void Compositor::layout() {
   if (root_layer_)
-    root_layer_->SendDamagedRect();
+    root_layer_->SendDamagedRects();
 }
 
 void Compositor::applyScrollAndScale(const WebKit::WebSize& scrollDelta,
diff --git a/ui/gfx/compositor/layer.cc b/ui/gfx/compositor/layer.cc
index b49e642..f4853d7 100644
--- a/ui/gfx/compositor/layer.cc
+++ b/ui/gfx/compositor/layer.cc
@@ -277,10 +277,11 @@ void Layer::SetColor(SkColor color) {
 bool Layer::SchedulePaint(const gfx::Rect& invalid_rect) {
   if (type_ == LAYER_SOLID_COLOR || !delegate_)
     return false;
-  if (damaged_rect_.IsEmpty())
-    damaged_rect_ = invalid_rect;
-  else
-    damaged_rect_ = damaged_rect_.Union(invalid_rect);
+  damaged_region_.op(invalid_rect.x(),
+                     invalid_rect.y(),
+                     invalid_rect.right(),
+                     invalid_rect.bottom(),
+                     SkRegion::kUnion_Op);
   ScheduleDraw();
   return true;
 }
@@ -291,21 +292,26 @@ void Layer::ScheduleDraw() {
     compositor->ScheduleDraw();
 }
 
-void Layer::SendDamagedRect() {
-  if (delegate_ && !damaged_rect_.IsEmpty()) {
-    WebKit::WebFloatRect web_rect(
-        damaged_rect_.x(),
-        damaged_rect_.y(),
-        damaged_rect_.width(),
-        damaged_rect_.height());
-    if (!web_layer_is_accelerated_)
-      web_layer_.to<WebKit::WebContentLayer>().invalidateRect(web_rect);
-    else
-      web_layer_.to<WebKit::WebExternalTextureLayer>().invalidateRect(web_rect);
-    damaged_rect_.SetRect(0, 0, 0, 0);
+void Layer::SendDamagedRects() {
+  if (delegate_ && !damaged_region_.isEmpty()) {
+    for (SkRegion::Iterator iter(damaged_region_);
+         !iter.done(); iter.next()) {
+      const SkIRect& damaged = iter.rect();
+      WebKit::WebFloatRect web_rect(
+          damaged.x(),
+          damaged.y(),
+          damaged.width(),
+          damaged.height());
+      if (!web_layer_is_accelerated_)
+        web_layer_.to<WebKit::WebContentLayer>().invalidateRect(web_rect);
+      else
+        web_layer_.to<WebKit::WebExternalTextureLayer>().invalidateRect(
+            web_rect);
+    }
+    damaged_region_.setEmpty();
   }
   for (size_t i = 0; i < children_.size(); ++i)
-    children_[i]->SendDamagedRect();
+    children_[i]->SendDamagedRects();
 }
 
 void Layer::SuppressPaint() {
diff --git a/ui/gfx/compositor/layer.h b/ui/gfx/compositor/layer.h
index d4efc38..e5c4134 100644
--- a/ui/gfx/compositor/layer.h
+++ b/ui/gfx/compositor/layer.h
@@ -14,6 +14,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "third_party/skia/include/core/SkColor.h"
+#include "third_party/skia/include/core/SkRegion.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebContentLayerClient.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebLayer.h"
 #include "ui/gfx/rect.h"
@@ -185,8 +186,9 @@ class COMPOSITOR_EXPORT Layer :
   // SchedulePaint() for that.
   void ScheduleDraw();
 
-  // Sends damaged rect to |compostior_| to repaint the content.
-  void SendDamagedRect();
+  // Sends damaged rectangles recorded in |damaged_region_| to
+  // |compostior_| to repaint the content.
+  void SendDamagedRects();
 
   // Suppresses painting the content by disgarding damaged region and ignoring
   // new paint requests.
@@ -277,7 +279,7 @@ class COMPOSITOR_EXPORT Layer :
 
   // Union of damaged rects to be used when compositor is ready to
   // paint the content.
-  gfx::Rect damaged_rect_;
+  SkRegion damaged_region_;
 
   float opacity_;