[IMP] *: use a custom error class for all errors thrown by owl

This commit makes all errors thrown in owl use a custom error class. The
main point of this is to always wrap user-code errors that happen during
the owl lifecycle so that they can be treated uniformly in onError by
checking the cause property, and also allows user code to differenciate
owl errors from non-owl errors reliably at runtime.

src/runtime/lifecycle_hooks.ts

@@ -1,14 +1,21 @@
 import { getCurrent } from "./component_node";
-import { nodeErrorHandlers } from "./error_handling";
+import { nodeErrorHandlers, OwlError } from "./error_handling";
 
 const TIMEOUT = Symbol("timeout");
 function wrapError(fn: (...args: any[]) => any, hookName: string) {
-  const error = new Error(`The following error occurred in ${hookName}: `) as Error & {
+  const error = new OwlError(`The following error occurred in ${hookName}: `) as Error & {
     cause: any;
   };
-  const timeoutError = new Error(`${hookName}'s promise hasn't resolved after 3 seconds`);
+  const timeoutError = new OwlError(`${hookName}'s promise hasn't resolved after 3 seconds`);
   const node = getCurrent();
   return (...args: any[]) => {
+    const onError = (cause: any) => {
+      if (cause instanceof Error) {
+        error.cause = cause;
+        error.message += `"${cause.message}"`;
+      }
+      throw error;
+    };
     try {
       const result = fn(...args);
       if (result instanceof Promise) {
@@ -23,20 +30,11 @@ function wrapError(fn: (...args: any[]) => any, hookName: string) {
             }
           });
         }
-        return result.catch((cause) => {
-          error.cause = cause;
-          if (cause instanceof Error) {
-            error.message += `"${cause.message}"`;
-          }
-          throw error;
-        });
+        return result.catch(onError);
       }
       return result;
     } catch (cause) {
-      if (cause instanceof Error) {
-        error.message += `"${cause.message}"`;
-      }
-      throw error;
+      onError(cause);
     }
   };
 }