[css-layout-api] Convert to promise based API.

As above! This switches the API from being generator based, to promise
based.

This introduces the specification's work queue, which is run until
exhaustion. After the work queue has been run the given promise should
be resolved, (if not we fallback to block layout).

This also introduces the CustomLayoutScope, and CustomLayoutToken
which are used together.

The CustomLayoutToken is a heap allocated class held onto objects which
should only be used within a certain layout pass. E.g. you cannot
hold onto a fragment from a previous layout pass, and use it within
the current layout pass.

This is managed by a stack allocated CustomLayoutScope, which once
destroyed marks the CustomLayoutToken as "detached". Any object which
has a "detached" token shouldn't be used.

The CustomLayoutScope is also used to hold onto the work queue.

Bug: 726125
Change-Id: Ic435c8c50fe3d3779f068b41eada815253d0b78b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1716035
Commit-Queue: Ian Kilpatrick <[email protected]>
Reviewed-by: Koji Ishii <[email protected]>
Cr-Commit-Position: refs/heads/master@{#684927}

Author: bfgeek

css/css-layout-api/auto-block-size-absolute.https.html

@@ -60,8 +60,8 @@
 
 <script id="code" type="text/worklet">
 registerLayout('block-size-100', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 100};
   }
 });

css/css-layout-api/auto-block-size-flex.https.html

@@ -42,14 +42,14 @@
 
 <script id="code" type="text/worklet">
 registerLayout('block-size-100', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 100};
   }
 });
 registerLayout('block-size-50', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 50};
   }
 });

css/css-layout-api/auto-block-size-floats.https.html

@@ -44,8 +44,8 @@
 
 <script id="code" type="text/worklet">
 registerLayout('block-size-100', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 100};
   }
 });

css/css-layout-api/auto-block-size-inflow.https.html

@@ -50,8 +50,8 @@
 
 <script id="code" type="text/worklet">
 registerLayout('block-size-100', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 100};
   }
 });

css/css-layout-api/auto-block-size-negative.https.html

@@ -38,8 +38,8 @@
 
 <script id="code" type="text/worklet">
 registerLayout('block-size-negative', class {
-  *intrinsicSizes() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: -100};
   }
 });

css/css-layout-api/box-tree-registered.https.html

@@ -55,8 +55,8 @@
 
 <script id="code" type="text/worklet">
 registerLayout('registered', class {
-  *intrinsicSizes() {}
-  *layout() { throw Error(); }
+  async intrinsicSizes() {}
+  async layout() { throw Error(); }
 });
 </script>
 

css/css-layout-api/constraints-data-function-failure.https.html

@@ -29,18 +29,17 @@
 
 <script id="code" type="text/worklet">
 registerLayout('parent', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout([child], edges, constraints, styleMap) {
+  async intrinsicSizes() {}
+  async layout([child], edges, constraints, styleMap) {
     let childFragment = null;
 
     try {
-      childFragment = yield child.layoutNextFragment({
+      childFragment = await child.layoutNextFragment({
         data: { fn: function() {} }
       });
     } catch(e) {
       // Success! The structured cloning algorithm should have thrown an error.
-      childFragment = yield child.layoutNextFragment({});
+      childFragment = await child.layoutNextFragment({});
       return {autoBlockSize: 100, childFragments: [childFragment]};
     }
 
@@ -49,9 +48,8 @@
 });
 
 registerLayout('child', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 0};
   }
 });

css/css-layout-api/constraints-data-sab-failure.https.html

@@ -29,18 +29,17 @@
 
 <script id="code" type="text/worklet">
 registerLayout('parent', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout([child], edges, constraints, styleMap) {
+  async intrinsicSizes() {}
+  async layout([child], edges, constraints, styleMap) {
     let childFragment = null;
 
     try {
-      childFragment = yield child.layoutNextFragment({
+      childFragment = await child.layoutNextFragment({
         data: { sab: new SharedArrayBuffer(4) }
       });
     } catch(e) {
       // Success! The structured cloning algorithm should have thrown an error.
-      childFragment = yield child.layoutNextFragment({});
+      childFragment = await child.layoutNextFragment({});
       return {autoBlockSize: 100, childFragments: [childFragment]};
     }
 
@@ -49,9 +48,8 @@
 });
 
 registerLayout('child', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout() {
+  async intrinsicSizes() {}
+  async layout() {
     return {autoBlockSize: 0};
   }
 });

css/css-layout-api/constraints-data.https.html

@@ -35,11 +35,10 @@
 };
 
 registerLayout('parent', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout([child], edges, constraints, styleMap) {
+  async intrinsicSizes() {}
+  async layout([child], edges, constraints, styleMap) {
 
-    const childFragment = yield child.layoutNextFragment({data: DATA});
+    const childFragment = await child.layoutNextFragment({data: DATA});
 
     // If the child's block-size is 100 the structured cloning worked.
     if (childFragment.blockSize === 100) {
@@ -51,9 +50,8 @@
 });
 
 registerLayout('child', class {
-  *intrinsicSizes() {}
-  *layout() {}
-  *layout(children, edges, constraints, styleMap) {
+  async intrinsicSizes() {}
+  async layout(children, edges, constraints, styleMap) {
     // Use JSON.stringify to make sure the structured cloning worked.
     if (constraints.data !== DATA &&
         JSON.stringify(constraints.data) === JSON.stringify(DATA)) {

css/css-layout-api/fallback-constructor-error.https.html

@@ -40,8 +40,8 @@
 <script id="code" type="text/worklet">
 registerLayout('throwing-ctor', class {
   constructor() { throw Error('fail!'); }
-  *intrinsicSizes() {}
-  *layout() {}
+  async intrinsicSizes() {}
+  async layout() {}
 });
 </script>