Bug 1444434 - Free the Gecko profiler screenshots structures in the WebRender renderer when profiling stops r=kvark

Differential Revision: https://phabricator.services.mozilla.com/D23964

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

gfx/webrender_bindings/RendererScreenshotGrabber.cpp

@@ -18,7 +18,7 @@ void RendererScreenshotGrabber::MaybeGrabScreenshot(
 
     GrabScreenshot(aRenderer, aWindowSize);
   } else if (mProfilerScreenshots) {
-    Destroy();
+    Destroy(aRenderer);
   }
 }
 
@@ -30,14 +30,16 @@ void RendererScreenshotGrabber::MaybeProcessQueue(Renderer* aRenderer) {
 
     ProcessQueue(aRenderer);
   } else if (mProfilerScreenshots) {
-    Destroy();
+    Destroy(aRenderer);
   }
 }
 
-void RendererScreenshotGrabber::Destroy() {
+void RendererScreenshotGrabber::Destroy(Renderer* aRenderer) {
   mQueue.Clear();
   mCurrentFrameQueueItem = Nothing();
   mProfilerScreenshots = nullptr;
+
+  wr_renderer_release_profiler_structures(aRenderer);
 }
 
 void RendererScreenshotGrabber::GrabScreenshot(

gfx/webrender_bindings/RendererScreenshotGrabber.h

@@ -44,8 +44,11 @@ class RendererScreenshotGrabber final {
  private:
   /**
    * Drop all our allocated memory when we are no longer profiling.
+   *
+   * This will also instruct WebRender to drop all its Gecko profiler
+   * associated memory.
    */
-  void Destroy();
+  void Destroy(Renderer* aRenderer);
 
   /**
    * Actually grab a screenshot from WebRender.

gfx/webrender_bindings/src/bindings.rs

@@ -715,6 +715,11 @@ pub extern "C" fn wr_renderer_map_and_recycle_screenshot(
     )
 }
 
+#[no_mangle]
+pub extern "C" fn wr_renderer_release_profiler_structures(renderer: &mut Renderer) {
+    renderer.release_profiler_structures();
+}
+
 // Call wr_renderer_render() before calling this function.
 #[no_mangle]
 pub unsafe extern "C" fn wr_renderer_readback(renderer: &mut Renderer,

gfx/wr/webrender/src/renderer.rs

@@ -2632,6 +2632,14 @@ impl Renderer {
         }
     }
 
+    pub fn release_profiler_structures(&mut self) {
+        if let Some(async_screenshots) = self.async_screenshots.take() {
+            self.device.begin_frame();
+            async_screenshots.deinit(&mut self.device);
+            self.device.end_frame();
+        }
+    }
+
     #[cfg(not(feature = "debugger"))]
     fn get_screenshot_for_debugger(&mut self) -> String {
         // Avoid unused param warning.