Revert of Discard compositor frames from unloaded web content

cc/ipc/struct_traits_unittest.cc

 // Copyright 2016 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 "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "cc/input/selection.h"
 #include "cc/ipc/copy_output_request_struct_traits.h"
 #include "cc/ipc/traits_test_service.mojom.h"
 #include "cc/output/copy_output_result.h"
@@ skipping 222 matching lines @@
   resource.id = tr_id;
   resource.format = tr_format;
   resource.filter = tr_filter;
   resource.size = tr_size;
 
   // CompositorFrameMetadata constants.
   const float device_scale_factor = 2.6f;
   const gfx::Vector2dF root_scroll_offset(1234.5f, 6789.1f);
   const float page_scale_factor = 1337.5f;
   const gfx::SizeF scrollable_viewport_size(1337.7f, 1234.5f);
-  const uint32_t content_source_id = 3;
 
   CompositorFrame input;
   input.metadata.device_scale_factor = device_scale_factor;
   input.metadata.root_scroll_offset = root_scroll_offset;
   input.metadata.page_scale_factor = page_scale_factor;
   input.metadata.scrollable_viewport_size = scrollable_viewport_size;
   input.render_pass_list.push_back(std::move(render_pass));
   input.resource_list.push_back(resource);
-  input.metadata.content_source_id = content_source_id;
 
   mojom::TraitsTestServicePtr proxy = GetTraitsTestProxy();
   CompositorFrame output;
   proxy->EchoCompositorFrame(std::move(input), &output);
 
   EXPECT_EQ(device_scale_factor, output.metadata.device_scale_factor);
   EXPECT_EQ(root_scroll_offset, output.metadata.root_scroll_offset);
   EXPECT_EQ(page_scale_factor, output.metadata.page_scale_factor);
   EXPECT_EQ(scrollable_viewport_size, output.metadata.scrollable_viewport_size);
-  EXPECT_EQ(content_source_id, output.metadata.content_source_id);
 
   ASSERT_EQ(1u, output.resource_list.size());
   TransferableResource out_resource = output.resource_list[0];
   EXPECT_EQ(tr_id, out_resource.id);
   EXPECT_EQ(tr_format, out_resource.format);
   EXPECT_EQ(tr_filter, out_resource.filter);
   EXPECT_EQ(tr_size, out_resource.size);
 
   EXPECT_EQ(1u, output.render_pass_list.size());
   const RenderPass* out_render_pass = output.render_pass_list[0].get();
@@ skipping 916 matching lines @@
   EXPECT_EQ(u_plane_resource_id, out_quad->u_plane_resource_id());
   EXPECT_EQ(v_plane_resource_id, out_quad->v_plane_resource_id());
   EXPECT_EQ(a_plane_resource_id, out_quad->a_plane_resource_id());
   EXPECT_EQ(color_space, out_quad->color_space);
   EXPECT_EQ(resource_offset, out_quad->resource_offset);
   EXPECT_EQ(resource_multiplier, out_quad->resource_multiplier);
   EXPECT_EQ(bits_per_channel, out_quad->bits_per_channel);
 }
 
 }  // namespace cc