cc: Do not ignore layers without valid priorities during eviction.

cc/layers/picture_layer_impl_perftest.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/picture_layer_impl.h"
 
 #include "cc/debug/lap_timer.h"
 #include "cc/test/fake_impl_proxy.h"
 #include "cc/test/fake_layer_tree_host_impl.h"
 #include "cc/test/fake_output_surface.h"
@@ skipping 112 matching lines @@
     host_impl_.pending_tree()->UpdateDrawProperties();
 
     TreePriority priorities[] = {SAME_PRIORITY_FOR_BOTH_TREES,
                                  SMOOTHNESS_TAKES_PRIORITY,
                                  NEW_CONTENT_TAKES_PRIORITY};
     int priority_count = 0;
     timer_.Reset();
     do {
       int count = num_tiles;
       PictureLayerImpl::LayerEvictionTileIterator it(
-          pending_layer_, priorities[priority_count]);
+          pending_layer_, nullptr, priorities[priority_count]);
       while (count--) {
         ASSERT_TRUE(it) << "count: " << count;
         ASSERT_TRUE(*it != nullptr) << "count: " << count;
         ++it;
       }
       priority_count = (priority_count + 1) % arraysize(priorities);
       timer_.NextLap();
     } while (!timer_.HasTimeLimitExpired());
 
     perf_test::PrintResult("layer_eviction_tile_iterator_construct_and_iterate",
@@ skipping 11 matching lines @@
         gfx::ScrollOffset(viewport.x(), viewport.y()));
     host_impl_.pending_tree()->UpdateDrawProperties();
 
     TreePriority priorities[] = {SAME_PRIORITY_FOR_BOTH_TREES,
                                  SMOOTHNESS_TAKES_PRIORITY,
                                  NEW_CONTENT_TAKES_PRIORITY};
     int priority_count = 0;
     timer_.Reset();
     do {
       PictureLayerImpl::LayerEvictionTileIterator it(
-          pending_layer_, priorities[priority_count]);
+          pending_layer_, nullptr, priorities[priority_count]);
       priority_count = (priority_count + 1) % arraysize(priorities);
       timer_.NextLap();
     } while (!timer_.HasTimeLimitExpired());
 
     perf_test::PrintResult("layer_eviction_tile_iterator_construct",
                            "",
                            test_name,
                            timer_.LapsPerSecond(),
                            "runs/s",
                            true);
@@ skipping 91 matching lines @@
 
   RunEvictionIteratorConstructTest("0_0_100x100", gfx::Rect(0, 0, 100, 100));
   RunEvictionIteratorConstructTest("5000_0_100x100",
                                    gfx::Rect(5000, 0, 100, 100));
   RunEvictionIteratorConstructTest("9999_0_100x100",
                                    gfx::Rect(9999, 0, 100, 100));
 }
 
 }  // namespace
 }  // namespace cc