Adjust weight ranges in FontDescription::Lighter/BolderWeight

Since the (CSS) parser allows numeric weight values in the range
[1, 1000], adjust the ranges in FontDescription::Lighter/BolderWeight
to match that.
Also factor in that the values can have fractions (by implicitly
truncating them) and simplify the range check since there's now a
set of adjacent intervals in practice.

Bug: 828747
Change-Id: I5fe3405ca45ed8016530d995976e36a6ebbcf366
Reviewed-on: https://chromium-review.googlesource.com/995452Reviewed-by: Dominik Röttsches <drott@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#548448}

third_party/WebKit/LayoutTests/TestExpectations

@@ -2911,7 +2911,7 @@ crbug.com/666993 external/wpt/requestidlecallback/callback-idle-periods.html [ T
 
 # Crashes with DCHECK enabled, but not on normal Release builds.
 crbug.com/809935 external/wpt/css/css-fonts/variations/font-style-interpolation.html [ Timeout ]
-crbug.com/828748 external/wpt/css/css-fonts/variations/font-weight-lighter-bolder.html [ Pass Crash Failure ]
+crbug.com/809956 external/wpt/css/css-fonts/variations/font-weight-lighter-bolder.html [ Failure ]
 crbug.com/626703 external/wpt/css/css-ui/text-overflow-011.html [ Failure Crash Pass ]
 crbug.com/626703 external/wpt/workers/opaque-origin.html [ Failure Crash Timeout ]
 crbug.com/626703 external/wpt/html/rendering/non-replaced-elements/margin-collapsing-quirks/multicol-quirks-mode.html [ Pass Crash ]

third_party/WebKit/Source/platform/fonts/FontDescription.cpp

@@ -114,22 +114,26 @@ bool FontDescription::operator==(const FontDescription& other) const {
 }
 
 FontSelectionValue FontDescription::LighterWeight(FontSelectionValue weight) {
-  if (weight >= FontSelectionValue(100) && weight <= FontSelectionValue(500))
+  // TODO(fs): Adjust to match table in
+  // https://drafts.csswg.org/css-fonts-4/#font-weight-prop
+  if (weight < FontSelectionValue(501))
     return FontSelectionValue(100);
-  if (weight >= FontSelectionValue(600) && weight <= FontSelectionValue(700))
+  if (weight < FontSelectionValue(701))
     return FontSelectionValue(400);
-  if (weight >= FontSelectionValue(800) && weight <= FontSelectionValue(900))
+  if (weight <= FontSelectionValue(1000))
     return FontSelectionValue(700);
   NOTREACHED();
   return NormalWeightValue();
 }
 
 FontSelectionValue FontDescription::BolderWeight(FontSelectionValue weight) {
-  if (weight >= FontSelectionValue(100) && weight <= FontSelectionValue(300))
+  // TODO(fs): Adjust to match table in
+  // https://drafts.csswg.org/css-fonts-4/#font-weight-prop
+  if (weight < FontSelectionValue(301))
     return FontSelectionValue(400);
-  if (weight >= FontSelectionValue(400) && weight <= FontSelectionValue(500))
+  if (weight < FontSelectionValue(501))
     return FontSelectionValue(700);
-  if (weight >= FontSelectionValue(600) && weight <= FontSelectionValue(900))
+  if (weight <= FontSelectionValue(1000))
     return FontSelectionValue(900);
   NOTREACHED();
   return NormalWeightValue();