cc: Ignore offscreen tiles for activation

cc: Ignore offscreen tiles for activation

Remove the overenthusiastic DCHECK from PictureLayerImpl to make sure
that every tile that intersects the visible content rect also has a
distance to the viewport of zero.  Because the projection of the
viewport is done more precisely than the enclosing rect for the visible
content rect, it may be possible for a tile to be outside the viewport
but inside the visible content rect.

Therefore, the current DCHECKS are bogus.  Instead, skip these tiles
because they're not truly required for activation.

R=reveman@chromium.org
BUG=243437
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=203063

[danakj, 2013-05-29 10:49:19]

LGTM a test for this scenario would be nice to verify u picked the tiles in the
viewport and only those.

[commit-bot: I haz the power, 2013-05-29 19:28:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/16160005/4001

[commit-bot: I haz the power, 2013-05-29 19:28:17]

Failed to apply patch for cc/layers/picture_layer_impl_unittest.cc:
While running patch -p1 --forward --force --no-backup-if-mismatch;
  patching file cc/layers/picture_layer_impl_unittest.cc
  Hunk #1 FAILED at 825.
  1 out of 1 hunk FAILED -- saving rejects to file
cc/layers/picture_layer_impl_unittest.cc.rej

Patch:       cc/layers/picture_layer_impl_unittest.cc
Index: cc/layers/picture_layer_impl_unittest.cc
diff --git a/cc/layers/picture_layer_impl_unittest.cc
b/cc/layers/picture_layer_impl_unittest.cc
index
0695ba1c28c4ce191ca11a818a616cd87576d421..499574bdd26f5805ec3556eeed660650b6388643
100644
--- a/cc/layers/picture_layer_impl_unittest.cc
+++ b/cc/layers/picture_layer_impl_unittest.cc
@@ -825,6 +825,71 @@ TEST_F(PictureLayerImplTest, MarkRequiredNullTiles) {
   // It should be safe to call this (and MarkVisibleResourcesAsRequired)
   // on a layer with no recordings.
   host_impl_.pending_tree()->UpdateDrawProperties();
+  pending_layer_->MarkVisibleResourcesAsRequired();
+}
+
+TEST_F(PictureLayerImplTest, MarkRequiredOffscreenTiles) {
+  gfx::Size tile_size(100, 100);
+  gfx::Size layer_bounds(200, 100);
+
+  scoped_refptr<FakePicturePileImpl> pending_pile =
+      FakePicturePileImpl::CreateFilledPile(tile_size, layer_bounds);
+  SetupPendingTree(pending_pile);
+
+  pending_layer_->set_fixed_tile_size(tile_size);
+  ASSERT_TRUE(pending_layer_->CanHaveTilings());
+  PictureLayerTiling* tiling = pending_layer_->AddTiling(1.f);
+  host_impl_.pending_tree()->UpdateDrawProperties();
+  EXPECT_EQ(tiling->resolution(), HIGH_RESOLUTION);
+
+  // Fake set priorities.
+  int tile_count = 0;
+  for (PictureLayerTiling::CoverageIterator iter(
+           tiling,
+           pending_layer_->contents_scale_x(),
+           gfx::Rect(pending_layer_->visible_content_rect()));
+       iter;
+       ++iter) {
+    if (!*iter)
+      continue;
+    Tile* tile = *iter;
+    TilePriority priority;
+    priority.resolution = HIGH_RESOLUTION;
+    if (++tile_count % 2) {
+      priority.time_to_visible_in_seconds = 0.f;
+      priority.distance_to_visible_in_pixels = 0.f;
+    } else {
+      priority.time_to_visible_in_seconds = 1.f;
+      priority.distance_to_visible_in_pixels = 1.f;
+    }
+    tile->SetPriority(PENDING_TREE, priority);
+  }
+
+  pending_layer_->MarkVisibleResourcesAsRequired();
+
+  int num_visible = 0;
+  int num_offscreen = 0;
+
+  for (PictureLayerTiling::CoverageIterator iter(
+           tiling,
+           pending_layer_->contents_scale_x(),
+           gfx::Rect(pending_layer_->visible_content_rect()));
+       iter;
+       ++iter) {
+    if (!*iter)
+      continue;
+    const Tile* tile = *iter;
+    if (tile->priority(PENDING_TREE).distance_to_visible_in_pixels == 0.f) {
+      EXPECT_TRUE(tile->required_for_activation());
+      num_visible++;
+    } else {
+      EXPECT_FALSE(tile->required_for_activation());
+      num_offscreen++;
+    }
+  }
+
+  EXPECT_GT(num_visible, 0);
+  EXPECT_GT(num_offscreen, 0);
 }
 
 }  // namespace

[commit-bot: I haz the power, 2013-05-29 21:28:34]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/enne@chromium.org/16160005/4001

[commit-bot: I haz the power, 2013-05-30 04:39:59]

Change committed as 203063