[LayoutNG] Rename ShapingLineBreaker::kStartShouldBeSafe to kDontReshapeStart

The naming turned out to be confusing.

Bug: 636993
Cq-Include-Trybots: luci.chromium.try:linux_layout_tests_layout_ng
Change-Id: I16fb06f080caac6ef9356edb187fe8032ef8f9ef
Reviewed-on: https://chromium-review.googlesource.com/1133098Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#574389}

third_party/blink/renderer/core/layout/ng/inline/ng_line_breaker.cc

@@ -423,9 +423,9 @@ void NGLineBreaker::BreakText(NGInlineItemResult* item_result,
   available_width = std::max(LayoutUnit(0), available_width);
 
   // Use kStartShouldBeSafe if at the beginning of a line.
-  unsigned options = 0;
-  if (offset_ == line_info->StartOffset())
-    options |= ShapingLineBreaker::kStartShouldBeSafe;
+  unsigned options = ShapingLineBreaker::kDefaultOptions;
+  if (offset_ != line_info->StartOffset())
+    options |= ShapingLineBreaker::kDontReshapeStart;
 
   // Use kNoResultIfOverflow if 'break-word' and we're trying to break normally
   // because if this item overflows, we will rewind and break line again. The

third_party/blink/renderer/platform/fonts/shaping/shaping_line_breaker.cc

@@ -243,9 +243,9 @@ scoped_refptr<ShapeResult> ShapingLineBreaker::ShapeLine(
   unsigned candidate_break =
       result_->CachedOffsetForPosition(end_position) + range_start;
 
-  unsigned first_safe = (options & kStartShouldBeSafe)
-                            ? result_->CachedNextSafeToBreakOffset(start)
-                            : start;
+  unsigned first_safe = (options & kDontReshapeStart)
+                            ? start
+                            : result_->CachedNextSafeToBreakOffset(start);
   DCHECK_GE(first_safe, start);
   if (candidate_break >= range_end) {
     // The |result_| does not have glyphs to fill the available space,

third_party/blink/renderer/platform/fonts/shaping/shaping_line_breaker.h

@@ -66,9 +66,10 @@ class PLATFORM_EXPORT ShapingLineBreaker final {
   // Shapes a line of text by finding a valid and appropriate break opportunity
   // based on the shaping results for the entire paragraph.
   enum Options {
-    // Enforce the start to be safe-to-break. Set for the beginning of each
-    // wrapped line, but not for subsequent ShapeResults.
-    kStartShouldBeSafe = 1,
+    kDefaultOptions = 0,
+    // Disable reshpaing the start edge even if the start offset is not safe-
+    // to-break. Set if this is not at the start edge of a wrapped line.
+    kDontReshapeStart = 1,
     // Returns nullptr if this line overflows. When the word is very long, such
     // as URL or data, creating ShapeResult is expensive. Set this option to
     // suppress if ShapeResult is not needed when this line overflows.
@@ -81,7 +82,7 @@ class PLATFORM_EXPORT ShapingLineBreaker final {
   scoped_refptr<ShapeResult> ShapeLine(unsigned start_offset,
                                        LayoutUnit available_space,
                                        Result* result_out) {
-    return ShapeLine(start_offset, available_space, kStartShouldBeSafe,
+    return ShapeLine(start_offset, available_space, kDefaultOptions,
                      result_out);
   }