Update from https://crrev.com/312398

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 69e5272f55e451971198584ee80aa4b9b97774cb..356bb5f2387ecc1adeba0d7a13537d6aef63c1dd 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -5779,6 +5779,66 @@ class RasterizeWithGpuRasterizationCreatesResources : public LayerTreeHostTest {
 
 MULTI_THREAD_IMPL_TEST_F(RasterizeWithGpuRasterizationCreatesResources);
 
+class GpuRasterizationRasterizesVisibleOnly : public LayerTreeHostTest {
+ protected:
+  GpuRasterizationRasterizesVisibleOnly() : viewport_size_(1024, 2048) {}
+
+  void InitializeSettings(LayerTreeSettings* settings) override {
+    settings->impl_side_painting = true;
+    settings->gpu_rasterization_enabled = true;
+    settings->gpu_rasterization_forced = true;
+  }
+
+  void SetupTree() override {
+    client_.set_fill_with_nonsolid_color(true);
+
+    scoped_ptr<FakePicturePile> pile(new FakePicturePile);
+    scoped_refptr<FakePictureLayer> root =
+        FakePictureLayer::CreateWithRecordingSource(&client_, pile.Pass());
+    root->SetBounds(gfx::Size(viewport_size_.width(), 10000));
+    root->SetContentsOpaque(true);
+
+    layer_tree_host()->SetRootLayer(root);
+    LayerTreeHostTest::SetupTree();
+    layer_tree_host()->SetViewportSize(viewport_size_);
+  }
+
+  void BeginTest() override { PostSetNeedsCommitToMainThread(); }
+
+  DrawResult PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
+                                   LayerTreeHostImpl::FrameData* frame_data,
+                                   DrawResult draw_result) override {
+    EXPECT_EQ(4u, host_impl->resource_provider()->num_resources());
+
+    // Verify which tiles got resources using an eviction iterator, which has to
+    // return all tiles that have resources.
+    EvictionTilePriorityQueue eviction_queue;
+    host_impl->BuildEvictionQueue(&eviction_queue,
+                                  SAME_PRIORITY_FOR_BOTH_TREES);
+    int tile_count = 0;
+    for (; !eviction_queue.IsEmpty(); eviction_queue.Pop()) {
+      Tile* tile = eviction_queue.Top();
+      // Ensure this tile is within the viewport.
+      EXPECT_TRUE(tile->content_rect().Intersects(gfx::Rect(viewport_size_)));
+      // Ensure that the tile is 1/4 of the viewport tall (plus padding).
+      EXPECT_EQ(tile->content_rect().height(),
+                (viewport_size_.height() / 4) + 2);
+      ++tile_count;
+    }
+    EXPECT_EQ(4, tile_count);
+    EndTest();
+    return draw_result;
+  }
+
+  void AfterTest() override {}
+
+ private:
+  FakeContentLayerClient client_;
+  gfx::Size viewport_size_;
+};
+
+MULTI_THREAD_IMPL_TEST_F(GpuRasterizationRasterizesVisibleOnly);
+
 class LayerTreeHostTestContinuousDrawWhenCreatingVisibleTiles
     : public LayerTreeHostTest {
  protected: