[GN] Fix TargetPath in Visual Studio projects

GN assumes that output_dir is root_build_dir for executables.
If that not so, Visual Studio can't find an executable to run and debug.
To fix it we are changing TargetPath field from $(ProjectName)$(TargetExt).
to exact path to ninja target output. Not sure about chromium, but it makes
sense for some standalone configurations

R=avakulenko@chromium.org, dpranke@chromium.org

Change-Id: Id9ccb7be96cc11f9504f4ea5a6e6117e1c55247b
Reviewed-on: https://chromium-review.googlesource.com/852459
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#528626}

AUTHORS

@@ -323,6 +323,7 @@ Ion Rosca <rosca@adobe.com>
 Irmak Kavasoglu <irmakkavasoglu@gmail.com>
 Isaac Murchie <murchieisaac@gmail.com>
 Isaac Reilly <reillyi@amazon.com>
+Ivan Naydonov <samogot@gmail.com>
 Ivan Sham <ivansham@amazon.com>
 J. Ryan Stinnett <jryans@chromium.org>
 Jack Bates <jack@nottheoilrig.com>

tools/gn/visual_studio_writer.cc

@@ -512,6 +512,8 @@ bool VisualStudioWriter::WriteProjectFileContents(
 
   project.SubElement("PropertyGroup", XmlAttributes("Label", "UserMacros"));
 
+  std::string ninja_target = GetNinjaTarget(target);
+
   {
     std::unique_ptr<XmlElementWriter> properties =
         project.SubElement("PropertyGroup");
@@ -524,8 +526,7 @@ bool VisualStudioWriter::WriteProjectFileContents(
     }
     properties->SubElement("TargetName")->Text("$(ProjectName)");
     if (target->output_type() != Target::GROUP) {
-      properties->SubElement("TargetPath")
-          ->Text("$(OutDir)\\$(ProjectName)$(TargetExt)");
+      properties->SubElement("TargetPath")->Text("$(OutDir)\\" + ninja_target);
     }
   }
 
@@ -636,8 +637,6 @@ bool VisualStudioWriter::WriteProjectFileContents(
                     "$(VCTargetsPath)\\BuildCustomizations\\masm.targets"));
   project.SubElement("ImportGroup", XmlAttributes("Label", "ExtensionTargets"));
 
-  std::string ninja_target = GetNinjaTarget(target);
-
   {
     std::unique_ptr<XmlElementWriter> build =
         project.SubElement("Target", XmlAttributes("Name", "Build"));