Bug 1780385 - Remove canvas hit region api. r=jrmuizel

Add a pref for MouseEvent.region since that wasn't un-exposed. No other
browser supports it so we can probably safely remove it, but just in
case.

Differential Revision: https://phabricator.services.mozilla.com/D152274

accessible/generic/LocalAccessible.cpp

@@ -652,28 +652,6 @@ nsIFrame* LocalAccessible::FindNearestAccessibleAncestorFrame() {
 nsRect LocalAccessible::ParentRelativeBounds() {
   nsIFrame* frame = GetFrame();
   if (frame && mContent) {
-    if (mContent->GetProperty(nsGkAtoms::hitregion) && mContent->IsElement()) {
-      // This is for canvas fallback content
-      // Find a canvas frame the found hit region is relative to.
-      nsIFrame* canvasFrame = frame->GetParent();
-      if (canvasFrame) {
-        canvasFrame = nsLayoutUtils::GetClosestFrameOfType(
-            canvasFrame, LayoutFrameType::HTMLCanvas);
-      }
-
-      if (canvasFrame) {
-        if (auto* canvas =
-                dom::HTMLCanvasElement::FromNode(canvasFrame->GetContent())) {
-          if (auto* context = canvas->GetCurrentContext()) {
-            nsRect bounds;
-            if (context->GetHitRegionRect(mContent->AsElement(), bounds)) {
-              return bounds;
-            }
-          }
-        }
-      }
-    }
-
     nsIFrame* boundingFrame = FindNearestAccessibleAncestorFrame();
     nsRect result = nsLayoutUtils::GetAllInFlowRectsUnion(frame, boundingFrame);
 
@@ -711,30 +689,6 @@ nsRect LocalAccessible::ParentRelativeBounds() {
 nsRect LocalAccessible::RelativeBounds(nsIFrame** aBoundingFrame) const {
   nsIFrame* frame = GetFrame();
   if (frame && mContent) {
-    if (mContent->GetProperty(nsGkAtoms::hitregion) && mContent->IsElement()) {
-      // This is for canvas fallback content
-      // Find a canvas frame the found hit region is relative to.
-      nsIFrame* canvasFrame = frame->GetParent();
-      if (canvasFrame) {
-        canvasFrame = nsLayoutUtils::GetClosestFrameOfType(
-            canvasFrame, LayoutFrameType::HTMLCanvas);
-      }
-
-      // make the canvas the bounding frame
-      if (canvasFrame) {
-        *aBoundingFrame = canvasFrame;
-        if (auto* canvas =
-                dom::HTMLCanvasElement::FromNode(canvasFrame->GetContent())) {
-          if (auto* context = canvas->GetCurrentContext()) {
-            nsRect bounds;
-            if (context->GetHitRegionRect(mContent->AsElement(), bounds)) {
-              return bounds;
-            }
-          }
-        }
-      }
-    }
-
     *aBoundingFrame = nsLayoutUtils::GetContainingBlockForClientRect(frame);
     nsRect unionRect = nsLayoutUtils::GetAllInFlowRectsUnion(
         frame, *aBoundingFrame, nsLayoutUtils::RECTS_ACCOUNT_FOR_TRANSFORMS);

accessible/tests/browser/hittest/browser.ini

@@ -8,10 +8,6 @@ support-files =
   !/accessible/tests/mochitest/letters.gif
 
 [browser_test_browser.js]
-[browser_test_canvas_hitregion.js]
-skip-if =
-  os == "android"
-  apple_catalina && fission && !debug # high frequency intermittent, Bug 1714314
 [browser_test_general.js]
 [browser_test_shadowroot.js]
 [browser_test_zoom_text.js]

accessible/tests/mochitest/elm/a11y.ini

@@ -10,6 +10,5 @@ support-files =
 [test_listbox.xhtml]
 [test_MathMLSpec.html]
 [test_nsApplicationAcc.html]
-[test_canvas.html]
 [test_shadowroot.html]
 support-files = test_shadowroot_subframe.html

accessible/tests/mochitest/hittest/a11y.ini

@@ -4,8 +4,6 @@ support-files = zoom_tree.xhtml
   !/accessible/tests/mochitest/letters.gif
 
 [test_browser.html]
-[test_canvas_hitregion.html]
-skip-if = (os == "android")
 [test_general.html]
 [test_menu.xhtml]
 [test_shadowroot.html]