cc: Fix tiling raster iterator to process all tiles correctly.

cc/resources/picture_layer_tiling.cc

Index: cc/resources/picture_layer_tiling.cc
diff --git a/cc/resources/picture_layer_tiling.cc b/cc/resources/picture_layer_tiling.cc
index 20a57b8a0723e2dfa9a386130b18c763ed2e62f7..b9b900c4ae83c1c04a1ceeb74e6409665c3382a6 100644
--- a/cc/resources/picture_layer_tiling.cc
+++ b/cc/resources/picture_layer_tiling.cc
@@ -870,13 +870,23 @@ void PictureLayerTiling::TilingRasterTileIterator::AdvancePhase() {
   DCHECK_LT(type_, TilePriority::EVENTUALLY);
 
   do {
-    type_ = static_cast<TilePriority::PriorityBin>(type_ + 1);
-    if (type_ == TilePriority::EVENTUALLY) {
+    if (type_ == TilePriority::SOON && !skewport_processed_)
+      skewport_processed_ = true;
+    else
+      type_ = static_cast<TilePriority::PriorityBin>(type_ + 1);
+
+    if (type_ == TilePriority::SOON && skewport_processed_) {
       spiral_iterator_ = TilingData::SpiralDifferenceIterator(
           &tiling_->tiling_data_,
-          eventually_rect_in_content_space_,
+          soon_border_rect_in_content_space_,
           skewport_in_content_space_,
           visible_rect_in_content_space_);
+    } else if (type_ == TilePriority::EVENTUALLY) {
+      spiral_iterator_ = TilingData::SpiralDifferenceIterator(
+          &tiling_->tiling_data_,
+          eventually_rect_in_content_space_,
+          skewport_in_content_space_,
+          soon_border_rect_in_content_space_);
     }

[reveman, 2014/07/24 12:50:16]

I find this code a bit hard to understand. It might just be that I'm not very
familiar with the phases we go through in this iterator. Could you add a comment
above the loop that lists each phase and then some comments next to the code in
the loop that makes us enter a new phase and why?

[reveman, 2014/07/24 13:12:23]

See my comment on the other patch. Maybe an enum for the phase can clean this up
and remove the need for comments.

[vmpstr, 2014/07/24 16:33:14]

Done.

 
     while (spiral_iterator_) {
@@ -912,20 +922,8 @@ operator++() {
       case TilePriority::SOON:
         ++spiral_iterator_;
         if (!spiral_iterator_) {
-          if (skewport_processed_) {
-            AdvancePhase();
-            return *this;
-          }
-          skewport_processed_ = true;
-          spiral_iterator_ = TilingData::SpiralDifferenceIterator(
-              &tiling_->tiling_data_,
-              soon_border_rect_in_content_space_,
-              skewport_in_content_space_,
-              visible_rect_in_content_space_);
-          if (!spiral_iterator_) {
-            AdvancePhase();
-            return *this;
-          }
+          AdvancePhase();
+          return *this;
         }
         next_index = spiral_iterator_.index();
         break;