[core] Add `line-gradient` property

Porting of https://github.com/mapbox/mapbox-gl-js/pull/6303
See the link above for the description of the feature and
its limitations).

Based on patch from @lbud (Lauren Budorick).

3 files changed, 1 insertions, 4 deletions

diff --git a/scripts/generate-shaders.js b/scripts/generate-shaders.js
index 5532bd33cd..ddfdd036a3 100755
--- a/scripts/generate-shaders.js
+++ b/scripts/generate-shaders.js
@@ -8,8 +8,6 @@ const zlib = require('zlib');
 
 var shaders = require('../mapbox-gl-js/src/shaders');
 
-delete shaders.lineGradient;
-
 require('./style-code');
 
 let concatenated = '';
diff --git a/scripts/generate-style-code.js b/scripts/generate-style-code.js
index 236df0a921..f85c6d8fd0 100755
--- a/scripts/generate-style-code.js
+++ b/scripts/generate-style-code.js
@@ -114,7 +114,7 @@ global.defaultValue = function (property) {
     return '{}';
   }
 
-  if (property.name === 'heatmap-color') {
+  if (property['property-type'] === 'color-ramp') {
       return '{}';
   }
 
diff --git a/scripts/style-spec.js b/scripts/style-spec.js
index dd9a127b70..196adc0b32 100644
--- a/scripts/style-spec.js
+++ b/scripts/style-spec.js
@@ -1,4 +1,3 @@
 var spec = module.exports = require('../mapbox-gl-js/src/style-spec/reference/v8');
 
 // Make temporary modifications here when Native doesn't have all features that JS has.
-delete spec.paint_line['line-gradient'];