Round GPU tiles to multiple of 64 to work around CA scaling issues

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 <stddef.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 4759 matching lines @@
   host_impl()->SetHasGpuRasterizationTrigger(true);
   host_impl()->CommitComplete();
   EXPECT_EQ(host_impl()->gpu_rasterization_status(),
             GpuRasterizationStatus::ON);
   host_impl()->SetViewportSize(gfx::Size(2000, 2000));
 
   layer->set_gpu_raster_max_texture_size(host_impl()->device_viewport_size());
   result = layer->CalculateTileSize(gfx::Size(10000, 10000));
   EXPECT_EQ(result.width(),
             MathUtil::UncheckedRoundUp(
-                2000 + 2 * PictureLayerTiling::kBorderTexels, 4));
-  EXPECT_EQ(result.height(), 504);  // 500 + 2, 4-byte aligned.
+                2000 + 2 * PictureLayerTiling::kBorderTexels, 64));
+  EXPECT_EQ(result.height(), 512);  // 500 + 2, 64-byte aligned.
 
   // Clamp and round-up, when smaller than viewport.
   // Tile-height doubles to 50% when width shrinks to <= 50%.
   host_impl()->SetViewportSize(gfx::Size(1000, 1000));
   layer->set_gpu_raster_max_texture_size(host_impl()->device_viewport_size());
   result = layer->CalculateTileSize(gfx::Size(447, 10000));
   EXPECT_EQ(result.width(), 448);
-  EXPECT_EQ(result.height(), 504);  // 500 + 2, 4-byte aliged.
+  EXPECT_EQ(result.height(), 512);  // 500 + 2, 64-byte aliged.
 
   // Largest layer is 50% of viewport width (rounded up), and
   // 50% of viewport in height.
   result = layer->CalculateTileSize(gfx::Size(447, 400));
   EXPECT_EQ(result.width(), 448);
   EXPECT_EQ(result.height(), 448);
   result = layer->CalculateTileSize(gfx::Size(500, 499));
   EXPECT_EQ(result.width(), 512);
-  EXPECT_EQ(result.height(), 504);  // 500 + 2, 4-byte aligned.
+  EXPECT_EQ(result.height(), 512);  // 500 + 2, 64-byte aligned.
 }
 
 TEST_F(NoLowResPictureLayerImplTest, LowResWasHighResCollision) {
   gfx::Size layer_bounds(1300, 1900);
 
   float low_res_factor = host_impl()->settings().low_res_contents_scale_factor;
   SetupDefaultTrees(layer_bounds);
   ResetTilingsAndRasterScales();
 
   float page_scale = 2.f;
@@ skipping 214 matching lines @@
     EXPECT_FLOAT_EQ(expected_contents_scale,
                     pending_layer_ptr->picture_layer_tiling_set()
                         ->FindTilingWithResolution(HIGH_RESOLUTION)
                         ->contents_scale())
         << "ideal_contents_scale: " << ideal_contents_scale;
   }
 }
 
 }  // namespace
 }  // namespace cc