Bug 1542826 - Add a pref to control the debug server. r=gw

Differential Revision: https://phabricator.services.mozilla.com/D28358

--HG--
extra : moz-landing-system : lando

gfx/thebes/gfxPrefs.h

@@ -548,6 +548,7 @@ class gfxPrefs final {
   DECL_GFX_PREF(Live, "gfx.webrender.max-filter-ops-per-chain", WebRenderMaxFilterOpsPerChain, uint32_t, 64);
   DECL_GFX_PREF(Live, "gfx.webrender.picture-caching",         WebRenderPictureCaching, bool, false);
   DECL_GFX_PREF(Once, "gfx.webrender.split-render-roots",      WebRenderSplitRenderRoots, bool, false);
+  DECL_GFX_PREF(Live, "gfx.webrender.start-debug-server",      WebRenderStartDebugServer, bool, false);
 
   // Use vsync events generated by hardware
   DECL_GFX_PREF(Once, "gfx.work-around-driver-bugs",           WorkAroundDriverBugs, bool, true);

gfx/webrender_bindings/WebRenderAPI.cpp

@@ -78,6 +78,7 @@ class NewRenderer : public RendererEvent {
             aWindowId, mSize.width, mSize.height,
             supportLowPriorityTransactions,
             gfxPrefs::WebRenderPictureCaching() && supportPictureCaching,
+            gfxPrefs::WebRenderStartDebugServer(),
             compositor->gl(),
             aRenderThread.GetProgramCache()
                 ? aRenderThread.GetProgramCache()->Raw()

gfx/webrender_bindings/src/bindings.rs

@@ -1136,6 +1136,7 @@ pub extern "C" fn wr_window_new(window_id: WrWindowId,
                                 window_height: i32,
                                 support_low_priority_transactions: bool,
                                 enable_picture_caching: bool,
+                                start_debug_server: bool,
                                 gl_context: *mut c_void,
                                 program_cache: Option<&mut WrProgramCache>,
                                 shaders: Option<&mut WrShaders>,
@@ -1227,7 +1228,7 @@ pub extern "C" fn wr_window_new(window_id: WrWindowId,
         namespace_alloc_by_client: true,
         enable_picture_caching,
         allow_pixel_local_storage_support: false,
-        start_debug_server: false,
+        start_debug_server,
         ..Default::default()
     };
 

modules/libpref/init/all.js

@@ -981,6 +981,11 @@ pref("gfx.webrender.dl.dump-parent", false);
 pref("gfx.webrender.dl.dump-content", false);
 pref("gfx.webrender.picture-caching", true);
 pref("gfx.webrender.split-render-roots", false);
+#ifdef NIGHTLY_BUILD
+// Keep this pref hidden on non-nightly builds to avoid people accidentally
+// turning it on
+pref("gfx.webrender.start-debug-server", false);
+#endif
 
 pref("accessibility.browsewithcaret", false);
 pref("accessibility.warn_on_browsewithcaret", true);