cc: Fix impl-side painting flashing due to missing tiles

There was a bug where flashing could occur if a non-updated tiling was
used for activation.  As tiles only get created during
UpdateTilePriorities and null tiles are accepted for activation (under
the premise that there is nothing recorded there and tiles couldn't be
created), this could cause a premature activation and flashing content.

Fix this case by making sure that syncing a tiling always updates that
tiling if the tree is up to date and doesn't need update draw
properties.

Add checks to make sure that all tilings have been updated and the tree
itself is up to date when calling AreVisibleResourcesReady.

R=danakj@chromium.org
BUG=230540

Review URL: https://chromiumcodereview.appspot.com/14883003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198219 0039d316-1c4b-4281-b951-d872f2087c98

cc/layers/picture_image_layer_impl_unittest.cc

@@ -9,6 +9,7 @@
 #include "cc/test/fake_output_surface.h"
 #include "cc/test/fake_picture_layer_tiling_client.h"
 #include "cc/test/impl_side_painting_settings.h"
+#include "cc/trees/layer_tree_impl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
@@ -41,6 +42,10 @@ class PictureImageLayerImplTest : public testing::Test {
     return make_scoped_ptr(layer);
   }
 
+  void UpdateDrawProperties() {
+    host_impl_.pending_tree()->UpdateDrawProperties();
+  }
+
  private:
   FakeImplProxy proxy_;
   FakeLayerTreeHostImpl host_impl_;
@@ -67,12 +72,15 @@ TEST_F(PictureImageLayerImplTest, AreVisibleResourcesReady) {
   layer->SetBounds(gfx::Size(100, 200));
   layer->SetDrawsContent(true);
 
+  UpdateDrawProperties();
+
   float contents_scale_x;
   float contents_scale_y;
   gfx::Size content_bounds;
   layer->CalculateContentsScale(2.f, false,
                                 &contents_scale_x, &contents_scale_y,
                                 &content_bounds);
+  layer->UpdateTilePriorities();
 
   EXPECT_TRUE(layer->AreVisibleResourcesReady());
 }

cc/layers/picture_layer_impl.cc

@@ -522,6 +522,13 @@ void PictureLayerImpl::SyncTiling(
   if (!DrawsContent() || tiling->contents_scale() < MinimumContentsScale())
     return;
   tilings_->AddTiling(tiling->contents_scale());
+
+  // If this tree needs update draw properties, then the tiling will
+  // get updated prior to drawing or activation.  If this tree does not
+  // need update draw properties, then its transforms are up to date and
+  // we can create tiles for this tiling immediately.
+  if (!layer_tree_impl()->needs_update_draw_properties())
+    UpdateTilePriorities();
 }
 
 void PictureLayerImpl::SetIsMask(bool is_mask) {
@@ -555,6 +562,7 @@ ResourceProvider::ResourceId PictureLayerImpl::ContentsResourceId() const {
 
 bool PictureLayerImpl::AreVisibleResourcesReady() const {
   DCHECK(layer_tree_impl()->IsPendingTree());
+  DCHECK(!layer_tree_impl()->needs_update_draw_properties());
   DCHECK(ideal_contents_scale_);
 
   if (!tilings_->num_tilings())
@@ -586,6 +594,7 @@ bool PictureLayerImpl::AreVisibleResourcesReady() const {
   Region missing_region = rect;
   for (size_t i = 0; i < tilings_->num_tilings(); ++i) {
     PictureLayerTiling* tiling = tilings_->tiling_at(i);
+    DCHECK(tiling->has_ever_been_updated());
 
     if (tiling->contents_scale() < min_acceptable_scale)
       continue;

cc/resources/picture_layer_tiling.cc

@@ -288,10 +288,15 @@ void PictureLayerTiling::UpdateTilePriorities(
     double current_frame_time_in_seconds,
     bool store_screen_space_quads_on_tiles,
     size_t max_tiles_for_interest_area) {
-  if (ContentRect().IsEmpty())
+  if (!NeedsUpdateForFrameAtTime(current_frame_time_in_seconds)) {
+    // This should never be zero for the purposes of has_ever_been_updated().
+    DCHECK_NE(current_frame_time_in_seconds, 0.0);
     return;
-  if (!NeedsUpdateForFrameAtTime(current_frame_time_in_seconds))
+  }
+  if (ContentRect().IsEmpty()) {
+    last_impl_frame_time_in_seconds_ = current_frame_time_in_seconds;
     return;
+  }
 
   gfx::Rect viewport_in_content_space =
       gfx::ToEnclosingRect(gfx::ScaleRect(viewport_in_layer_space,

cc/resources/picture_layer_tiling.h

@@ -157,6 +157,10 @@ class CC_EXPORT PictureLayerTiling {
       int64 target_area,
       gfx::Rect bounding_rect);
 
+  bool has_ever_been_updated() const {
+    return last_impl_frame_time_in_seconds_ != 0.0;
+  }
+
  protected:
   typedef std::pair<int, int> TileMapKey;
   typedef base::hash_map<TileMapKey, scoped_refptr<Tile> > TileMap;