Revert "service: needs_chrome_source: search for binpkgs in virtual/target depgraph"

This reverts commit 043f6050e006158201de3a2139c509e8cc45e63d.

Reason for revert: Breaks the chrome source required check,
which is causing chrome source to always not be synced.

See b/292138028#comment28.

Original change's description:
> service: needs_chrome_source: search for binpkgs in virtual/target depgraph
>
> Rather than trying to emerge the chrome package directly to see if it
> has a binpkg, emerge the high-level virtual/target-os packages.  This
> will take into account things like changing deps/subslots that would
> cause a binpkg to be ignored that testing a package directly misses.
>
> BUG=b:292138028
> TEST=CQ passes
>
> Change-Id: I54d69afa88bd3346b4074c4dc2cfacc2d56e687e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4908599
> Commit-Queue: Mike Frysinger <vapier@chromium.org>
> Auto-Submit: Mike Frysinger <vapier@chromium.org>
> Reviewed-by: Alex Klein <saklein@chromium.org>
> Commit-Queue: Alex Klein <saklein@chromium.org>
> Tested-by: Mike Frysinger <vapier@chromium.org>

BUG=b:292138028

Change-Id: I8bd35ca02f067dece47d1de228334bf123f44123
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4918584
Auto-Submit: Jack Rosenthal <jrosenth@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Commit-Queue: Sergey Frolov <sfrolov@google.com>
diff --git a/lib/portage_util.py b/lib/portage_util.py
index 51193b8..9ebd091 100644
--- a/lib/portage_util.py
+++ b/lib/portage_util.py
@@ -2884,7 +2884,7 @@
         return failed_pkgs
 
 
-def HasPrebuilt(atom, board=None, extra_env=None, depgraph_root_packages=None):
+def HasPrebuilt(atom, board=None, extra_env=None):
     """Check if the atom's best visible version has a prebuilt available."""
     cmd = [
         os.path.join(
@@ -2895,9 +2895,6 @@
     if board:
         cmd += ["--build-target", board]
 
-    if depgraph_root_packages:
-        cmd += ["--depgraph-root-packages", " ".join(depgraph_root_packages)]
-
     if logging.getLogger().isEnabledFor(logging.DEBUG):
         cmd += ["--debug"]
 
diff --git a/scripts/has_prebuilt.py b/scripts/has_prebuilt.py
index 6ce8b79..c262283 100644
--- a/scripts/has_prebuilt.py
+++ b/scripts/has_prebuilt.py
@@ -34,11 +34,6 @@
         help="The build target that is being checked.",
     )
     parser.add_argument(
-        "--depgraph-root-packages",
-        action="split_extend",
-        help="Search the depgraph starting at these packages.",
-    )
-    parser.add_argument(
         "--output",
         type="path",
         required=True,
@@ -117,11 +112,7 @@
         ]
         if board:
             args.append("--board=%s" % board)
-        if opts.depgraph_root_packages:
-            args += [f"--reinstall-atoms={x.cp}" for x in bests.values()]
-            args += opts.depgraph_root_packages
-        else:
-            args.extend("=%s" % best.cpvr for best in bests.values())
+        args.extend("=%s" % best.cpvr for best in bests.values())
 
         generator = depgraph.DepGraphGenerator()
         logging.debug(
diff --git a/service/packages.py b/service/packages.py
index c689ed7..77e9ffb 100644
--- a/service/packages.py
+++ b/service/packages.py
@@ -1422,7 +1422,6 @@
     atom: str,
     build_target: "build_target_lib.BuildTarget" = None,
     useflags: Union[Iterable[str], str] = None,
-    depgraph_root_packages: Optional[List[package_info.PackageInfo]] = None,
 ) -> bool:
     """Check if a prebuilt exists.
 
@@ -1432,7 +1431,6 @@
             SDK if not provided.
         useflags: Any additional USE flags that should be set. May be a string
             of properly formatted USE flags, or an iterable of individual flags.
-        depgraph_root_packages: Packages to generate the depgraph from.
 
     Returns:
         True if there is an available prebuilt, False otherwise.
@@ -1449,12 +1447,7 @@
         existing = os.environ.get("USE", "")
         final_flags = "%s %s" % (existing, new_flags)
         extra_env = {"USE": final_flags.strip()}
-    return portage_util.HasPrebuilt(
-        atom,
-        board=board,
-        extra_env=extra_env,
-        depgraph_root_packages=depgraph_root_packages,
-    )
+    return portage_util.HasPrebuilt(atom, board=board, extra_env=extra_env)
 
 
 def builds(atom, build_target, packages=None):
@@ -1525,7 +1518,6 @@
                 chrome_cpvr,
                 build_target=build_target,
                 useflags=useflags,
-                depgraph_root_packages=packages,
             )
             if not has_chrome_prebuilt:
                 pkgs_needing_prebuilts.append(chrome_cpvr)
@@ -1534,10 +1526,7 @@
             if not builds_pkg:
                 continue
             prebuilt = has_prebuilt(
-                pkg,
-                build_target=build_target,
-                useflags=useflags,
-                depgraph_root_packages=packages,
+                pkg, build_target=build_target, useflags=useflags
             )
             has_follower_prebuilts &= prebuilt
             if not prebuilt:
diff --git a/service/packages_unittest.py b/service/packages_unittest.py
index 95e0762..0c0e938 100644
--- a/service/packages_unittest.py
+++ b/service/packages_unittest.py
@@ -927,10 +927,7 @@
 
         packages.has_prebuilt("cat/pkg-1.2.3", useflags="useflag")
         patch.assert_called_with(
-            "cat/pkg-1.2.3",
-            board=None,
-            extra_env={"USE": "useflag"},
-            depgraph_root_packages=None,
+            "cat/pkg-1.2.3", board=None, extra_env={"USE": "useflag"}
         )
 
     def test_env_use_flags(self):
@@ -945,27 +942,7 @@
         packages.has_prebuilt("cat/pkg-1.2.3", useflags=new_flags)
         expected = "%s %s" % (existing_flags, new_flags)
         patch.assert_called_with(
-            "cat/pkg-1.2.3",
-            board=None,
-            extra_env={"USE": expected},
-            depgraph_root_packages=None,
-        )
-
-    def test_depgraph_root_packages(self):
-        """Test root depgraph packages."""
-        # We don't really care about the result, just the package handling.
-        patch = self.PatchObject(portage_util, "HasPrebuilt", return_value=True)
-        os.unsetenv("USE")
-
-        depgraph_pkgs = ["virtual/target-os"]
-        packages.has_prebuilt(
-            "cat/pkg-1.2.3", depgraph_root_packages=depgraph_pkgs
-        )
-        patch.assert_called_with(
-            "cat/pkg-1.2.3",
-            board=None,
-            extra_env=mock.ANY,
-            depgraph_root_packages=depgraph_pkgs,
+            "cat/pkg-1.2.3", board=None, extra_env={"USE": expected}
         )