Revert of Discard compositor frames from unloaded web content

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 1f2059cb0c3ea1c3c1bd7d9bf17b64d037a71a42..eaf3c4756f5047cc5fe584dd6eeeec0577950b9c 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -7010,32 +7010,5 @@
 
 SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestSubmitFrameResources);
 
-// Ensure that content_source_id is propagated to the frame's metadata.
-class LayerTreeHostTestContentSourceId : public LayerTreeHostTest {
- protected:
-  void BeginTest() override {
-    layer_tree_host()->SetContentSourceId(5);
-    PostSetNeedsCommitToMainThread();
-  }
-
-  DrawResult PrepareToDrawOnThread(LayerTreeHostImpl* host_impl,
-                                   LayerTreeHostImpl::FrameData* frame_data,
-                                   DrawResult draw_result) override {
-    EXPECT_EQ(DRAW_SUCCESS, draw_result);
-    EXPECT_EQ(5U, host_impl->active_tree()->content_source_id());
-    return draw_result;
-  }
-
-  void DisplayReceivedCompositorFrameOnThread(
-      const CompositorFrame& frame) override {
-    EXPECT_EQ(5U, frame.metadata.content_source_id);
-    EndTest();
-  }
-
-  void AfterTest() override {}
-};
-
-SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestContentSourceId);
-
 }  // namespace
 }  // namespace cc