Add --headless flag to Windows

chrome/BUILD.gn

Index: chrome/BUILD.gn
diff --git a/chrome/BUILD.gn b/chrome/BUILD.gn
index 7a32fb0816a38d86a560407272321666be7804e1..131442dc5234502e0373e7f71a28bbfb90609cf3 100644
--- a/chrome/BUILD.gn
+++ b/chrome/BUILD.gn
@@ -336,6 +336,7 @@ if (is_win) {
       "//components/policy:generated",
       "//content/app/resources",
       "//crypto",
+      "//headless:headless_shell_main_lib",
       "//net:net_resources",
       "//ppapi/features",
       "//third_party/cld",
@@ -361,6 +362,8 @@ if (is_win) {
       "/DELAYLOAD:wsock32.dll",
     ]
 
+    configs += [ "//headless:headless_implementation" ]

[Sami, 2017/03/20 11:53:10]

This doesn't seem right: the implementation build should only be enabled when
building the headless library itself.

Are you getting some linker errors without this? Perhaps there's an export macro
missing for some function/symbol?

[dvallet, 2017/03/22 07:14:17]

Fixed, the reason is that ChromeMain calls HeadlesShellMain which uses
HEADLESS_EXPORT and this required exporting this in this library. But I don't
really think that we need to add the export to the main method and so the config
is not needed. 

+
     if (!is_component_build) {
       # This is a large module that can't do incremental linking in some
       # cases.
@@ -427,6 +430,7 @@ if (is_win) {
         "//components/browser_watcher:browser_watcher_client",
         "//components/crash/content/app",
         "//content/public/app:child",
+        "//headless:headless_shell_child_lib",
         "//pdf",
       ]