Bug 1966443: Make synthesizeMockDragAndDrop usable in plain mochitests r=edgar

Uses spawnChrome from a content process to initiate synthesizeMockDragAndDrop
in the parent process.  The checks in synthesizeMockDragAndDrop will not be
run since communicating back to content requires SpecialPowers.  So, in plain
mochitests the function will only be useful for the plain test itself.
(For example, tests can easily intercept expected drag/drop events and perform
their own behaviors/checks there.)

This patch also removes some cruft from the test framework's implementation and
improves logging integration.

Differential Revision: https://phabricator.services.mozilla.com/D259297

Author: davidp3

dom/ipc/BrowserChild.cpp

@@ -80,6 +80,7 @@
 #include "mozilla/layers/TouchActionHelper.h"
 #include "mozilla/layers/WebRenderLayerManager.h"
 #include "mozilla/widget/ScreenManager.h"
+#include "mozilla/widget/WidgetLogging.h"
 #include "nsCommandParams.h"
 #include "nsContentPermissionHelper.h"
 #include "nsContentUtils.h"
@@ -143,16 +144,6 @@ using namespace mozilla::layout;
 using namespace mozilla::widget;
 using mozilla::layers::GeckoContentController;
 
-extern mozilla::LazyLogModule sWidgetDragServiceLog;
-#define __DRAGSERVICE_LOG__(logLevel, ...) \
-  MOZ_LOG(sWidgetDragServiceLog, logLevel, __VA_ARGS__)
-#define DRAGSERVICE_LOGD(...) \
-  __DRAGSERVICE_LOG__(mozilla::LogLevel::Debug, (__VA_ARGS__))
-#define DRAGSERVICE_LOGI(...) \
-  __DRAGSERVICE_LOG__(mozilla::LogLevel::Info, (__VA_ARGS__))
-#define DRAGSERVICE_LOGE(...) \
-  __DRAGSERVICE_LOG__(mozilla::LogLevel::Error, (__VA_ARGS__))
-
 static const char BEFORE_FIRST_PAINT[] = "before-first-paint";
 
 static uint32_t sConsecutiveTouchMoveCount = 0;
@@ -2135,10 +2126,11 @@ mozilla::ipc::IPCResult BrowserChild::RecvRealDragEvent(
   nsCOMPtr<nsIDragSession> dragSession = GetDragSession();
   DRAGSERVICE_LOGD(
       "[%p] %s | aEvent.mMessage: %s | aDragAction: %u | aDropEffect: %u | "
-      "dragSession: %p",
+      "widgetRelativePt: (%d,%d) | dragSession: %p",
       this, __FUNCTION__,
       NS_ConvertUTF16toUTF8(dom::Event::GetEventName(aEvent.mMessage)).get(),
-      aDragAction, aDropEffect, dragSession.get());
+      aDragAction, aDropEffect, static_cast<int>(localEvent.mRefPoint.x),
+      static_cast<int>(localEvent.mRefPoint.y), dragSession.get());
   if (dragSession) {
     dragSession->SetDragAction(aDragAction);
     dragSession->SetTriggeringPrincipal(aPrincipal);

testing/mochitest/tests/SimpleTest/DragParentContextBase.sys.mjs

@@ -13,23 +13,12 @@ export class DragParentContextBase {
   // Browsing context that the related element is in
   browsingContext = null;
 
-  constructor(
-    aSubtypeName,
-    aBrowsingContext,
-    aParams,
-    aSpecialPowers,
-    aOk,
-    aIs,
-    aInfo
-  ) {
+  constructor(aSubtypeName, aBrowsingContext, aParams, aSpecialPowers) {
     Object.assign(this, aParams);
     this.params = aParams;
     this.subtypeName = aSubtypeName;
     this.browsingContext = aBrowsingContext;
     this.specialPowers = aSpecialPowers;
-    this.ok = aOk;
-    this.is = aIs;
-    this.info = aInfo;
   }
 
   getElementPositions() {

testing/mochitest/tests/SimpleTest/DragSourceParentContext.sys.mjs

@@ -7,16 +7,8 @@ import { DragParentContextBase } from "./DragParentContextBase.sys.mjs";
 
 /* global content */
 export class DragSourceParentContext extends DragParentContextBase {
-  constructor(aBrowsingContext, aParams, aSpecialPowers, aOk, aIs, aInfo) {
-    super(
-      "dragSource",
-      aBrowsingContext,
-      aParams,
-      aSpecialPowers,
-      aOk,
-      aIs,
-      aInfo
-    );
+  constructor(aBrowsingContext, aParams, aSpecialPowers) {
+    super("dragSource", aBrowsingContext, aParams, aSpecialPowers);
   }
 
   initialize() {

testing/mochitest/tests/SimpleTest/DragTargetParentContext.sys.mjs

@@ -7,16 +7,8 @@ import { DragParentContextBase } from "./DragParentContextBase.sys.mjs";
 
 /* global content */
 export class DragTargetParentContext extends DragParentContextBase {
-  constructor(aBrowsingContext, aParams, aSpecialPowers, aOk, aIs, aInfo) {
-    super(
-      "dragTarget",
-      aBrowsingContext,
-      aParams,
-      aSpecialPowers,
-      aOk,
-      aIs,
-      aInfo
-    );
+  constructor(aBrowsingContext, aParams, aSpecialPowers) {
+    super("dragTarget", aBrowsingContext, aParams, aSpecialPowers);
   }
 
   initialize() {