Auto merge of #20315 - kwonoj:feat-webrender-capture, r=jdm

feat(window): bind hotkey to trigger capture event

<!-- Please describe your changes on the following line: -->
Relates to #20295.

This PR intends to expose additional hotkey to window to allow capture webrender. Internally it adds one new `WindowEvent::CaptureWebRender` for those purpose. I took some liberty to make some decisions around which need to be reviewed & updated in PR.

- `Ctrl-shift-3` is binded to hotkey to follow described in Gecko's behavior. Is it good to go?
- Maybe do not need to create new event `CaptureWebRender` but reuse `ToggleWebRenderDebug`, having additional `WebRenderDebugOption` values?
: This sounds more right path for me, but `capture` isn't really `toggle` behavior to include capture into it.
- Capturing will create `capture_webrender` in cwd, creates new folder inside each time new capture stored
: Maybe it'd better to expose new cmdline args allow overrides, or some better way else. I took the simple approach to generate path without asking for it.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #20295 (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____
- This change has manually verified on local machines (mac, windows, linux).

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.gitignore

@@ -22,6 +22,7 @@
 Servo.app
 .config.mk.last
 /glfw
+capture_webrender/
 
 # Editors
 

components/compositing/Cargo.toml

@@ -27,5 +27,5 @@ servo_geometry = {path = "../geometry"}
 servo_url = {path = "../url"}
 style_traits = {path = "../style_traits"}
 time = "0.1.17"
-webrender = {git = "https://github.com/servo/webrender"}
+webrender = {git = "https://github.com/servo/webrender", features = ["capture"]}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}

components/compositing/compositor.rs

@@ -23,14 +23,15 @@ use script_traits::CompositorEvent::{MouseMoveEvent, MouseButtonEvent, TouchEven
 use servo_config::opts;
 use servo_geometry::DeviceIndependentPixel;
 use std::collections::HashMap;
+use std::env;
 use std::fs::File;
 use std::rc::Rc;
 use std::sync::mpsc::Sender;
 use std::time::{Duration, Instant};
 use style_traits::{CSSPixel, DevicePixel, PinchZoomFactor};
 use style_traits::cursor::CursorKind;
 use style_traits::viewport::ViewportConstraints;
-use time::{precise_time_ns, precise_time_s};
+use time::{now, precise_time_ns, precise_time_s};
 use touch::{TouchHandler, TouchAction};
 use webrender;
 use webrender_api::{self, DeviceUintRect, DeviceUintSize, HitTestFlags, HitTestResult};
@@ -1530,6 +1531,17 @@ impl<Window: WindowMethods> IOCompositor<Window> {
         txn.generate_frame();
         self.webrender_api.send_transaction(self.webrender_document, txn);
     }
+
+    pub fn capture_webrender(&mut self) {
+        match env::current_dir() {
+            Ok(current_dir) => {
+                let capture_id = now().to_timespec().sec.to_string();
+                let capture_path = current_dir.join("capture_webrender").join(capture_id);
+                self.webrender_api.save_capture(capture_path, webrender_api::CaptureBits::all());
+            },
+            Err(err) => println!("could not locate path to save captures: {:?}", err)
+        }
+    }
 }
 
 /// Why we performed a composite. This is used for debugging.

components/compositing/windowing.rs

@@ -84,6 +84,8 @@ pub enum WindowEvent {
     SelectBrowser(TopLevelBrowsingContextId),
     /// Toggles a debug flag in WebRender
     ToggleWebRenderDebug(WebRenderDebugOption),
+    /// Capture current WebRender
+    CaptureWebRender,
 }
 
 impl Debug for WindowEvent {
@@ -108,6 +110,7 @@ impl Debug for WindowEvent {
             WindowEvent::CloseBrowser(..) => write!(f, "CloseBrowser"),
             WindowEvent::SelectBrowser(..) => write!(f, "SelectBrowser"),
             WindowEvent::ToggleWebRenderDebug(..) => write!(f, "ToggleWebRenderDebug"),
+            WindowEvent::CaptureWebRender => write!(f, "CaptureWebRender"),
         }
     }
 }

components/servo/lib.rs

@@ -333,6 +333,10 @@ impl<Window> Servo<Window> where Window: WindowMethods + 'static {
                 self.compositor.toggle_webrender_debug(option);
             }
 
+            WindowEvent::CaptureWebRender => {
+                self.compositor.capture_webrender();
+            }
+
             WindowEvent::NewBrowser(url, response_chan) => {
                 let msg = ConstellationMsg::NewBrowser(url, response_chan);
                 if let Err(e) = self.constellation_chan.send(msg) {

ports/servo/glutin_app/window.rs

@@ -1230,6 +1230,9 @@ impl WindowMethods for Window {
                     self.event_queue.borrow_mut().push(WindowEvent::Quit);
                 }
             }
+            (_, Some('3'), _) => if mods ^ KeyModifiers::CONTROL == KeyModifiers::SHIFT {
+                self.event_queue.borrow_mut().push(WindowEvent::CaptureWebRender);
+            }
             (KeyModifiers::CONTROL, None, Key::F10) => {
                 let event = WindowEvent::ToggleWebRenderDebug(WebRenderDebugOption::RenderTargetDebug);
                 self.event_queue.borrow_mut().push(event);