Bug 1185482 - Remove gap between titlebar buttons and navigation toolbar r=dao

MozReview-Commit-ID: AD2opbF4Uxn

browser/base/content/browser-tabsintitlebar.js

@@ -176,6 +176,16 @@ var TabsInTitlebar = {
 
       // Begin setting CSS properties which will cause a reflow
 
+      if (AppConstants.MOZ_PHOTON_THEME &&
+          AppConstants.isPlatformAndVersionAtLeast("win", "10.0")) {
+        if (!menuHeight) {
+          titlebarContentHeight = Math.max(titlebarContentHeight, fullTabsHeight);
+          $("titlebar-buttonbox").style.height = titlebarContentHeight + "px";
+        } else {
+          $("titlebar-buttonbox").style.removeProperty("height");
+        }
+      }
+
       // If the menubar is around (menuHeight is non-zero), try to adjust
       // its full height (i.e. including margins) to match the titlebar,
       // by changing the menubar's bottom padding

toolkit/modules/AppConstants.jsm

@@ -362,4 +362,11 @@ this.AppConstants = Object.freeze({
     false,
 #endif
 
+  MOZ_PHOTON_THEME:
+#ifdef MOZ_PHOTON_THEME
+    true,
+#else
+    false,
+#endif
+
 });