Add GN output prefix override and allow empty output extensions.

tools/gn/target_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 "tools/gn/target.h"
 
 #include <utility>
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "tools/gn/build_settings.h"
@@ skipping 276 matching lines @@
   EXPECT_EQ("bar", with_prefix.GetComputedOutputName(false));
   EXPECT_EQ("libbar", with_prefix.GetComputedOutputName(true));
 
   // Target with a "lib" prefix that already has it applied. The prefix should
   // not duplicate something already in the target name.
   TestTarget dup_prefix(setup, "//foo:bar", Target::STATIC_LIBRARY);
   dup_prefix.set_output_name("libbar");
   ASSERT_TRUE(dup_prefix.OnResolved(&err));
   EXPECT_EQ("libbar", dup_prefix.GetComputedOutputName(false));
   EXPECT_EQ("libbar", dup_prefix.GetComputedOutputName(true));
+
+  // Target with an output prefix override should not a prefix.

[Dirk Pranke, 2016/04/07 21:43:54]

nit: s/should not a/should not have a/

+  TestTarget override_prefix(setup, "//foo:bar", Target::SHARED_LIBRARY);
+  override_prefix.set_output_prefix_override(true);
+  ASSERT_TRUE(dup_prefix.OnResolved(&err));
+  EXPECT_EQ("bar", override_prefix.GetComputedOutputName(false));
+  EXPECT_EQ("bar", override_prefix.GetComputedOutputName(true));
 }
 
 // Test visibility failure case.
 TEST(Target, VisibilityFails) {
   TestWithScope setup;
   Err err;
 
   TestTarget b(setup, "//private:b", Target::STATIC_LIBRARY);
   b.visibility().SetPrivate(b.label().dir());
   ASSERT_TRUE(b.OnResolved(&err));
@@ skipping 567 matching lines @@
   ASSERT_EQ(c.bundle_data().file_rules().size(), 1u);
   ASSERT_EQ(c.bundle_data().file_rules()[0].sources().size(), 1u);
   ASSERT_EQ(c.bundle_data().bundle_deps().size(), 1u);
 
   // E does not have any bundle_data information but gets a list of
   // bundle_deps to propagate them during target resolution.
   ASSERT_TRUE(e.bundle_data().file_rules().empty());
   ASSERT_TRUE(e.bundle_data().asset_catalog_sources().empty());
   ASSERT_EQ(e.bundle_data().bundle_deps().size(), 2u);
 }