Route WebRender pref changes through the RenderBackend.

The overlap between debug flags and debug commands is a bit of a mess,
and this patch does not entirely clean it up. But this at least means
that the RenderBackend can react to pref changes in Firefox.

Differential Revision: https://phabricator.services.mozilla.com/D11958

webrender/src/renderer.rs

@@ -30,6 +30,7 @@ use api::{MemoryReport, VoidPtrToSizeFn};
 use api::{RenderApiSender, RenderNotifier, TexelRect, TextureTarget};
 use api::{channel};
 use api::DebugCommand;
+pub use api::DebugFlags;
 use api::channel::PayloadReceiverHelperMethods;
 use batch::{BatchKind, BatchTextures, BrushBatchKind};
 #[cfg(any(feature = "capture", feature = "replay"))]
@@ -237,26 +238,6 @@ impl BatchKind {
     }
 }
 
-bitflags! {
-    #[derive(Default)]
-    pub struct DebugFlags: u32 {
-        const PROFILER_DBG          = 1 << 0;
-        const RENDER_TARGET_DBG     = 1 << 1;
-        const TEXTURE_CACHE_DBG     = 1 << 2;
-        const GPU_TIME_QUERIES      = 1 << 3;
-        const GPU_SAMPLE_QUERIES    = 1 << 4;
-        const DISABLE_BATCHING      = 1 << 5;
-        const EPOCHS                = 1 << 6;
-        const COMPACT_PROFILER      = 1 << 7;
-        const ECHO_DRIVER_MESSAGES  = 1 << 8;
-        const NEW_FRAME_INDICATOR   = 1 << 9;
-        const NEW_SCENE_INDICATOR   = 1 << 10;
-        const SHOW_OVERDRAW         = 1 << 11;
-        const GPU_CACHE_DBG         = 1 << 12;
-        const SLOW_FRAME_INDICATOR  = 1 << 13;
-    }
-}
-
 fn flag_changed(before: DebugFlags, after: DebugFlags, select: DebugFlags) -> Option<bool> {
     if before & select != after & select {
         Some(after.contains(select))
@@ -2436,6 +2417,9 @@ impl Renderer {
                     }
                 }
             }
+            DebugCommand::SetFlags(flags) => {
+                self.set_debug_flags(flags);
+            }
         }
     }
 

webrender_api/src/api.rs

@@ -664,6 +664,9 @@ pub enum DebugCommand {
     /// Causes the low priority scene builder to pause for a given amount of miliseconds
     /// each time it processes a transaction.
     SimulateLongLowPrioritySceneBuild(u32),
+    /// Sets the provided debug flags. This may overlap with some of the functionality
+    /// above.
+    SetFlags(DebugFlags),
 }
 
 #[derive(Clone, Deserialize, Serialize)]
@@ -913,7 +916,26 @@ impl RenderApiSender {
             next_id: Cell::new(ResourceId(0)),
         }
     }
+}
 
+bitflags! {
+    #[derive(Default, Deserialize, Serialize)]
+    pub struct DebugFlags: u32 {
+        const PROFILER_DBG          = 1 << 0;
+        const RENDER_TARGET_DBG     = 1 << 1;
+        const TEXTURE_CACHE_DBG     = 1 << 2;
+        const GPU_TIME_QUERIES      = 1 << 3;
+        const GPU_SAMPLE_QUERIES    = 1 << 4;
+        const DISABLE_BATCHING      = 1 << 5;
+        const EPOCHS                = 1 << 6;
+        const COMPACT_PROFILER      = 1 << 7;
+        const ECHO_DRIVER_MESSAGES  = 1 << 8;
+        const NEW_FRAME_INDICATOR   = 1 << 9;
+        const NEW_SCENE_INDICATOR   = 1 << 10;
+        const SHOW_OVERDRAW         = 1 << 11;
+        const GPU_CACHE_DBG         = 1 << 12;
+        const SLOW_FRAME_INDICATOR  = 1 << 13;
+    }
 }
 
 pub struct RenderApi {
@@ -1013,6 +1035,11 @@ impl RenderApi {
         rx.recv().unwrap()
     }
 
+    pub fn set_debug_flags(&self, flags: DebugFlags) {
+        let cmd = DebugCommand::SetFlags(flags);
+        self.api_sender.send(ApiMsg::DebugCommand(cmd)).unwrap();
+    }
+
     pub fn shut_down(&self) {
         self.api_sender.send(ApiMsg::ShutDown).unwrap();
     }