Added flags for PrintBrowser mode

printing/features/features.gni

Index: printing/features/features.gni
diff --git a/printing/features/features.gni b/printing/features/features.gni
index 651b7a7a221169526a914fd03227e8cadc8e0559..60b7c09a9f5af6c0988fd0cff74da4ad16628afc 100644
--- a/printing/features/features.gni
+++ b/printing/features/features.gni
@@ -16,6 +16,11 @@ declare_args() {
   use_cups = (is_desktop_linux || is_mac) && !is_chromecast
 }
 
+declare_args() {
+  # Enable printing mode browsing. Implies enable_print_preview.

[Vitaly Buka (NO REVIEWS), 2016/12/12 05:29:48]

Code implies opposite.

[gozzard, 2016/12/14 23:14:48]

The implication logic is in another file. This determines the default value for
the build flag. Fixed

+  enable_print_browser = enable_print_preview
+}
+
 if ((enable_basic_printing && is_win) || enable_print_preview) {
   # Windows basic printing or print preview requires pdf enabled.
   assert(enable_pdf,