Don't add implicit deps to copy commands in GN.

tools/gn/ninja_copy_target_writer_unittest.cc

 // Copyright (c) 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 <algorithm>
 #include <sstream>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/file_template.h"
 #include "tools/gn/ninja_copy_target_writer.h"
@@ skipping 19 matching lines @@
 
   const char expected_linux[] =
       "build input1.out: copy ../../foo/input1.txt\n"
       "build input2.out: copy ../../foo/input2.txt\n"
       "\n"
       "build obj/foo/bar.stamp: stamp input1.out input2.out\n";
   std::string out_str = out.str();
   EXPECT_EQ(expected_linux, out_str);
 }
 
-// Tests a single file with no output pattern and a toolchain dependency.
+// Tests a single file with no output pattern.
 TEST(NinjaCopyTargetWriter, ToolchainDeps) {
   TestWithScope setup;
   setup.settings()->set_target_os(Settings::LINUX);
   setup.build_settings()->SetBuildDir(SourceDir("//out/Debug/"));
   Target target(setup.settings(), Label(SourceDir("//foo/"), "bar"));
   target.set_output_type(Target::COPY_FILES);
 
-  // Toolchain dependency. Here we make a target in the same toolchain for
-  // simplicity, but in real life (using the Builder) this would be rejected
-  // because it would be a circular dependency (the target depends on its
-  // toolchain, and the toolchain depends on this target).
-  Target toolchain_dep_target(setup.settings(),
-                              Label(SourceDir("//foo/"), "setup"));
-  toolchain_dep_target.set_output_type(Target::ACTION);
-  setup.toolchain()->deps().push_back(LabelTargetPair(&toolchain_dep_target));
-
   target.sources().push_back(SourceFile("//foo/input1.txt"));
 
   target.action_values().outputs().push_back("//out/Debug/output.out");
 
   std::ostringstream out;
   NinjaCopyTargetWriter writer(&target, setup.toolchain(), out);
   writer.Run();
 
   const char expected_linux[] =
-      "build obj/foo/bar.inputdeps.stamp: stamp obj/foo/setup.stamp\n"
-      "build output.out: copy ../../foo/input1.txt | "
-          "obj/foo/bar.inputdeps.stamp\n"
+      "build output.out: copy ../../foo/input1.txt\n"
       "\n"
       "build obj/foo/bar.stamp: stamp output.out\n";
   std::string out_str = out.str();
   EXPECT_EQ(expected_linux, out_str);
 }