webgl: Add destructors for texture, program, shader, buffer and framebuffer

This allows to cleanup resources earlier if they stop being used. Right
now all resources were cleaned up when the context was destroyed, this is
a slightly better approach.

We ignore the possible failure of the send() call, since we don't keep
track of these resources from the `WebGLRenderingContext` structure, so
a texture could be destroyed after the context and give us problems.

components/script/dom/webglbuffer.rs

@@ -71,7 +71,13 @@ impl WebGLBuffer {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteBuffer(self.id))).unwrap();
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteBuffer(self.id)));
         }
     }
 }
+
+impl Drop for WebGLBuffer {
+    fn drop(&mut self) {
+        self.delete();
+    }
+}

components/script/dom/webglframebuffer.rs

@@ -60,7 +60,13 @@ impl WebGLFramebuffer {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteFramebuffer(self.id))).unwrap();
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteFramebuffer(self.id)));
         }
     }
 }
+
+impl Drop for WebGLFramebuffer {
+    fn drop(&mut self) {
+        self.delete();
+    }
+}

components/script/dom/webglprogram.rs

@@ -58,7 +58,7 @@ impl WebGLProgram {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteProgram(self.id))).unwrap();
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteProgram(self.id)));
         }
     }
 
@@ -125,3 +125,9 @@ impl WebGLProgram {
         Ok(receiver.recv().unwrap())
     }
 }
+
+impl Drop for WebGLProgram {
+    fn drop(&mut self) {
+        self.delete();
+    }
+}

components/script/dom/webglrenderbuffer.rs

@@ -59,7 +59,7 @@ impl WebGLRenderbuffer {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteRenderbuffer(self.id))).unwrap();
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteRenderbuffer(self.id)));
         }
     }
 }

components/script/dom/webglshader.rs

@@ -121,7 +121,7 @@ impl WebGLShader {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteShader(self.id))).unwrap()
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteShader(self.id)));
         }
     }
 
@@ -152,3 +152,9 @@ impl WebGLShader {
         *self.source.borrow_mut() = Some(source);
     }
 }
+
+impl Drop for WebGLShader {
+    fn drop(&mut self) {
+        self.delete();
+    }
+}

components/script/dom/webgltexture.rs

@@ -78,7 +78,7 @@ impl WebGLTexture {
     pub fn delete(&self) {
         if !self.is_deleted.get() {
             self.is_deleted.set(true);
-            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteTexture(self.id))).unwrap();
+            let _ = self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteTexture(self.id)));
         }
     }
 
@@ -145,3 +145,9 @@ impl WebGLTexture {
         }
     }
 }
+
+impl Drop for WebGLTexture {
+    fn drop(&mut self) {
+        self.delete();
+    }
+}