Fix specs that broke when accounting for horizontal scrollbar height

spec/display-buffer-spec.coffee

@@ -979,6 +979,7 @@ describe "DisplayBuffer", ->
   describe "::setScrollLeft", ->
     beforeEach ->
       displayBuffer.manageScrollPosition = true
+      displayBuffer.setLineHeight(10)
       displayBuffer.setDefaultCharWidth(10)
 
     it "disallows negative values", ->
@@ -1001,6 +1002,7 @@ describe "DisplayBuffer", ->
       displayBuffer.manageScrollPosition = true
       displayBuffer.setLineHeight(10)
       displayBuffer.setDefaultCharWidth(10)
+      displayBuffer.setHorizontalScrollbarHeight(0)
 
       displayBuffer.setHeight(50)
       displayBuffer.setWidth(50)

spec/editor-spec.coffee

@@ -698,6 +698,7 @@ describe "Editor", ->
         editor.setHorizontalScrollMargin(2)
         editor.setLineHeight(10)
         editor.setDefaultCharWidth(10)
+        editor.setHorizontalScrollbarHeight(0)
         editor.setHeight(5.5 * 10)
         editor.setWidth(5.5 * 10)
 
@@ -1138,6 +1139,7 @@ describe "Editor", ->
           editor.setDefaultCharWidth(10)
           editor.setHeight(50)
           editor.setWidth(50)
+          editor.setHorizontalScrollbarHeight(0)
           expect(editor.getScrollTop()).toBe 0
 
           editor.setSelectedBufferRange([[5, 6], [6, 8]], autoscroll: true)
@@ -3098,6 +3100,7 @@ describe "Editor", ->
       editor.setDefaultCharWidth(10)
       editor.setHeight(50)
       editor.setWidth(50)
+      editor.setHorizontalScrollbarHeight(0)
       expect(editor.getScrollTop()).toBe 0
       expect(editor.getScrollLeft()).toBe 0
 

src/display-buffer.coffee

@@ -32,6 +32,7 @@ class DisplayBuffer extends Model
 
   verticalScrollMargin: 2
   horizontalScrollMargin: 6
+  horizontalScrollbarHeight: 15
 
   constructor: ({tabLength, @editorWidthInChars, @tokenizedBuffer, buffer}={}) ->
     super
@@ -126,7 +127,9 @@ class DisplayBuffer extends Model
   verticallyScrollable: ->
     @getScrollHeight() > @getClientHeight()
 
-  getHorizontalScrollbarHeight: -> 15
+  getHorizontalScrollbarHeight: -> @horizontalScrollbarHeight
+
+  setHorizontalScrollbarHeight: (@horizontalScrollbarHeight) -> @horizontalScrollbarHeight
 
   getWidth: ->
     @width ? @getScrollWidth()

src/editor.coffee

@@ -1895,6 +1895,8 @@ class Editor extends Model
 
   verticallyScrollable: -> @displayBuffer.verticallyScrollable()
 
+  setHorizontalScrollbarHeight: (height) -> @displayBuffer.setHorizontalScrollbarHeight(height)
+
   # Deprecated: Call {::joinLines} instead.
   joinLine: ->
     deprecate("Use Editor::joinLines() instead")