Fix not to wrap in 'nowrap' elements

When a word in 'nowrap' element fits but its trailing space does not, issue 561997 fixed not to wrap before the 'nowrap' element. The fix, however, creates a wrap opportunity even if 'nowrap' content follows. This patch ensures the fix is valid only if no content follows or autowrap content follows; i.e., only when we really have a break opportunity after the space. Ideally, the original fix should have been done when the line breaker reads the next item. But we have a lot of places that call FitsOnLine() without 'ExcludeWhitespace' option and probably some of them are not correct. To make the fix safer, this patch limits the original fix instead of cleaning up all FitsOnLine() calls. Change-Id: I78c499cc6c1d7c30261e031ec19124ae9d3fbcf1 Bug: 561997, 840755 Reviewed-on: https://chromium-review.googlesource.com/1053341Reviewed-by: Emil A Eklund <eae@chromium.org> Commit-Queue: Emil A Eklund <eae@chromium.org> Cr-Commit-Position: refs/heads/master@{#557556}

Fix not to wrap in 'nowrap' elements
When a word in 'nowrap' element fits but its trailing space does not, issue 561997 fixed not to wrap before the 'nowrap' element. The fix, however, creates a wrap opportunity even if 'nowrap' content follows. This patch ensures the fix is valid only if no content follows or autowrap content follows; i.e., only when we really have a break opportunity after the space. Ideally, the original fix should have been done when the line breaker reads the next item. But we have a lot of places that call FitsOnLine() without 'ExcludeWhitespace' option and probably some of them are not correct. To make the fix safer, this patch limits the original fix instead of cleaning up all FitsOnLine() calls. Change-Id: I78c499cc6c1d7c30261e031ec19124ae9d3fbcf1 Bug: 561997, 840755 Reviewed-on: https://chromium-review.googlesource.com/1053341Reviewed-by: Emil A Eklund <eae@chromium.org> Commit-Queue: Emil A Eklund <eae@chromium.org> Cr-Commit-Position: refs/heads/master@{#557556}
6f6afe2f · Koji Ishii · Commit Bot · 035c0c8f · 6f6afe2f · 6f6afe2f
Commit 6f6afe2f authored May 10, 2018 by Koji Ishii Committed by Commit Bot May 10, 2018
2 changed files
--- a/third_party/WebKit/LayoutTests/fast/text/whitespace/nowrap-space-inside.html
+++ b/third_party/WebKit/LayoutTests/fast/text/whitespace/nowrap-space-inside.html
+<!DOCTYPE html>
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<style>
+.container {
+  width:200px;
+  background-color:#eee;
+}
+.spacer {
+  height:10px; background-color:black;
+}
+.nowrap {
+  white-space: nowrap;
+}
+</style>
+<body>
+<p>Spaces in nowrap shold not break when the text before it fits but the space overflows.</p>
+<template id=template>
+  <div class=container>
+    <img class=spacer />
+    <span class=nowrap><span>foo</span> <span>bar</span></span>
+  </div>
+</template>
+<script>
+run();
+function run() {
+  let tests = [];
+  for (let width = 170; width < 180; width++) {
+    let element = template.content.children[0].cloneNode(true);
+    let spacer = element.querySelector('img');
+    spacer.style.width = width + 'px';
+    document.body.appendChild(element);
+    tests.push({width: width, element: element});
+  }
+  let results = [];
+  for (let t of tests) {
+    test(() => {
+      let nowrap = t.element.querySelector('.nowrap');
+      let child1 = nowrap.children[0];
+      let child2 = nowrap.children[1];
+      assert_equals(child1.offsetTop, child2.offsetTop);
+    }, `width: ${t.width}`);
+  }
+}
+</script>
+</body>
--- a/third_party/blink/renderer/core/layout/line/breaking_context_inline_headers.h
+++ b/third_party/blink/renderer/core/layout/line/breaking_context_inline_headers.h
@@ -1491,7 +1491,11 @@ inline void BreakingContext::CommitAndUpdateLineBreakIfNeeded() {
  bool check_for_break = auto_wrap_;
  if (width_.CommittedWidth() && !width_.FitsOnLine() &&
      line_break_.GetLineLayoutItem() && curr_ws_ == EWhiteSpace::kNowrap) {
-    if (width_.FitsOnLine(0, kExcludeWhitespace)) {
+    // If this nowrap item fits but its trailing spaces does not, and if the
+    // next item is auto-wrap, break before the next item.
+    // TODO(kojii): This case should be handled when we read next item.
+    if (width_.FitsOnLine(0, kExcludeWhitespace) &&
+        (!next_object_ || next_object_.StyleRef().AutoWrap())) {
      width_.Commit();
      line_break_.MoveToStartOf(next_object_);
    }