cc: Remove the layer content_bounds() and use bounds() instead.

And remove the content_bounds from DrawProperties.

They are always equal now (outside of some legacy tests).

R=enne@chromium.org, enne, vmpstr
BUG=413479
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1179133004.

Cr-Commit-Position: refs/heads/master@{#334979}

• cc/BUILD.gn[diff]
• cc/blink/web_layer_impl_fixed_bounds_unittest.cc[diff]
• cc/cc.gyp[diff]
• cc/cc_tests.gyp[diff]
• cc/debug/debug_rect_history.cc[diff]
• cc/debug/picture_record_benchmark.cc[diff]
• cc/debug/rasterize_and_record_benchmark_impl.cc[diff]
• cc/layers/contents_scaling_layer.cc[Deleted - diff]
• cc/layers/contents_scaling_layer.h[Deleted - diff]
• cc/layers/contents_scaling_layer_unittest.cc[Deleted - diff]
• cc/layers/delegated_renderer_layer_impl.cc[diff]
• cc/layers/delegated_renderer_layer_impl_unittest.cc[diff]
• cc/layers/draw_properties.h[diff]
• cc/layers/io_surface_layer_impl.cc[diff]
• cc/layers/layer.cc[diff]
• cc/layers/layer.h[diff]
• cc/layers/layer_impl.cc[diff]
• cc/layers/layer_impl.h[diff]
• cc/layers/layer_impl_unittest.cc[diff]
• cc/layers/nine_patch_layer_impl.cc[diff]
• cc/layers/render_surface_impl.cc[diff]
• cc/layers/scrollbar_layer_unittest.cc[diff]
• cc/layers/solid_color_layer_impl.cc[diff]
• cc/layers/solid_color_scrollbar_layer_impl.cc[diff]
• cc/layers/texture_layer_impl.cc[diff]
• cc/layers/ui_resource_layer_impl.cc[diff]
• cc/layers/video_layer_impl.cc[diff]
• cc/trees/layer_tree_host_common.cc[diff]
• cc/trees/layer_tree_host_common_perftest.cc[diff]
• cc/trees/layer_tree_host_common_unittest.cc[diff]
• cc/trees/layer_tree_host_impl.cc[diff]
• cc/trees/layer_tree_host_impl_unittest.cc[diff]
• cc/trees/layer_tree_impl.cc[diff]
• cc/trees/layer_tree_impl_unittest.cc[diff]