cc: Don't rasterize large layers at maximum scale before scale animations

cc/layers/picture_layer_impl_unittest.cc

 // Copyright 2013 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 <algorithm>
 #include <limits>
 #include <set>
 #include <utility>
@@ skipping 1845 matching lines @@
   ASSERT_TRUE(fake_output_surface->InitializeAndSetContext3d(
       TestContextProvider::Create()));
 
   // These will crash PictureLayerImpl if this is not true.
   ASSERT_TRUE(host_impl_.pending_tree()->needs_update_draw_properties());
   ASSERT_TRUE(host_impl_.active_tree()->needs_update_draw_properties());
   host_impl_.active_tree()->UpdateDrawProperties();
 }
 
 TEST_F(PictureLayerImplTest, HighResTilingDuringAnimationForCpuRasterization) {
-  gfx::Size tile_size(host_impl_.settings().default_tile_size);
-  SetupDefaultTrees(tile_size);
+  gfx::Size layer_bounds(100, 100);
+  gfx::Size viewport_size(1000, 1000);
+  SetupDefaultTrees(layer_bounds);
+  host_impl_.SetViewportSize(viewport_size);
 
   float contents_scale = 1.f;
   float device_scale = 1.3f;
   float page_scale = 1.4f;
   float maximum_animation_scale = 1.f;
   bool animating_transform = false;
 
   SetContentsScaleOnBothLayers(contents_scale,
                                device_scale,
                                page_scale,
@@ skipping 63 matching lines @@
   // Once we stop animating, a new high-res tiling should be created.
   animating_transform = false;
   contents_scale = 4.f;
 
   SetContentsScaleOnBothLayers(contents_scale,
                                device_scale,
                                page_scale,
                                maximum_animation_scale,
                                animating_transform);
   EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 4.f);
+
+  // When animating with a maxmium animation scale factor that is so large
+  // that the layer grows larger than the viewport at this scale, a new
+  // high-res tiling should get created at the animation's initial scale, not
+  // at its maximum scale.
+  animating_transform = true;
+  contents_scale = 2.f;
+  maximum_animation_scale = 11.f;
+
+  SetContentsScaleOnBothLayers(contents_scale,
+                               device_scale,
+                               page_scale,
+                               maximum_animation_scale,
+                               animating_transform);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 2.f);
+
+  // Once we stop animating, a new high-res tiling should be created.
+  animating_transform = false;
+  contents_scale = 11.f;
+
+  SetContentsScaleOnBothLayers(contents_scale,
+                               device_scale,
+                               page_scale,
+                               maximum_animation_scale,
+                               animating_transform);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 11.f);
+
+  // When animating with a maxmium animation scale factor that is so large
+  // that the layer grows larger than the viewport at this scale, and where
+  // the intial source scale is < 1, a new high-res tiling should get created
+  // at source scale 1.
+  animating_transform = true;
+  contents_scale = 0.1f;
+  maximum_animation_scale = 11.f;
+
+  SetContentsScaleOnBothLayers(contents_scale,
+                               device_scale,
+                               page_scale,
+                               maximum_animation_scale,
+                               animating_transform);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), device_scale * page_scale);
+
+  // Once we stop animating, a new high-res tiling should be created.
+  animating_transform = false;
+  contents_scale = 11.f;
+
+  SetContentsScaleOnBothLayers(contents_scale,
+                               device_scale,
+                               page_scale,
+                               maximum_animation_scale,
+                               animating_transform);
+  EXPECT_BOTH_EQ(HighResTiling()->contents_scale(), 11.f);
 }
 
 TEST_F(PictureLayerImplTest, LayerRasterTileIterator) {
   gfx::Size tile_size(100, 100);
   gfx::Size layer_bounds(1000, 1000);
 
   scoped_refptr<FakePicturePileImpl> pending_pile =
       FakePicturePileImpl::CreateFilledPile(tile_size, layer_bounds);
 
   SetupPendingTree(pending_pile);
@@ skipping 1554 matching lines @@
 
   host_impl_.tile_manager()->InitializeTilesWithResourcesForTesting(all_tiles);
 
   VerifyEvictionConsidersOcclusion(pending_layer_,
                                    total_expected_occluded_tile_count);
   VerifyEvictionConsidersOcclusion(active_layer_,
                                    total_expected_occluded_tile_count);
 }
 }  // namespace
 }  // namespace cc