Don't inherit source sets across static libs in GN.

tools/gn/target_unittest.cc

Index: tools/gn/target_unittest.cc
diff --git a/tools/gn/target_unittest.cc b/tools/gn/target_unittest.cc
index 860dcaf1b0d4e36550c9dae7cd17775f20a8a064..6219374c947ad75c1dc2e39cab26b6a1dc3d673d 100644
--- a/tools/gn/target_unittest.cc
+++ b/tools/gn/target_unittest.cc
@@ -199,3 +199,42 @@ TEST_F(TargetTest, ForwardDependentConfigsFromGroups) {
   ASSERT_EQ(1u, a.direct_dependent_configs().size());
   ASSERT_EQ(&direct, a.direct_dependent_configs()[0].ptr);
 }
+
+TEST_F(TargetTest, InheritLibs) {
+  // Create a dependency chain:
+  //   A (executable) -> B (shared lib) -> C (static lib) -> D (source set)
+  Target a(&settings_, Label(SourceDir("//foo/"), "a"));
+  a.set_output_type(Target::EXECUTABLE);
+  Target b(&settings_, Label(SourceDir("//foo/"), "b"));
+  b.set_output_type(Target::SHARED_LIBRARY);
+  Target c(&settings_, Label(SourceDir("//foo/"), "c"));
+  c.set_output_type(Target::STATIC_LIBRARY);
+  Target d(&settings_, Label(SourceDir("//foo/"), "d"));
+  d.set_output_type(Target::SOURCE_SET);
+  a.deps().push_back(LabelTargetPair(&b));
+  b.deps().push_back(LabelTargetPair(&c));
+  c.deps().push_back(LabelTargetPair(&d));
+
+  d.OnResolved();
+  c.OnResolved();
+  b.OnResolved();
+  a.OnResolved();
+
+  // C should have D in its inherited libs.
+  const std::set<const Target*>& c_inherited = c.inherited_libraries();
+  EXPECT_EQ(1u, c_inherited.size());
+  EXPECT_TRUE(c_inherited.find(&d) != c_inherited.end());
+
+  // B should have C in its inherited libs, but not D (the static library will
+  // include the source sets's code).
+  const std::set<const Target*>& b_inherited = b.inherited_libraries();
+  EXPECT_EQ(1u, b_inherited.size());
+  EXPECT_TRUE(b_inherited.find(&c) != b_inherited.end());
+
+  // A should have B in its inherited libs, but not any others (the shared
+  // library will include the static library, which will include the source
+  // set).
+  const std::set<const Target*>& a_inherited = a.inherited_libraries();
+  EXPECT_EQ(1u, a_inherited.size());
+  EXPECT_TRUE(a_inherited.find(&b) != a_inherited.end());
+}