Bug 1119527 - Implement canvas clearHitRegions. r=gw280, r=bz

dom/canvas/CanvasRenderingContext2D.cpp

@@ -3230,6 +3230,12 @@ CanvasRenderingContext2D::RemoveHitRegion(const nsAString& id)
   }
 }
 
+void
+CanvasRenderingContext2D::ClearHitRegions()
+{
+  mHitRegionsOptions.Clear();
+}
+
 bool
 CanvasRenderingContext2D::GetHitRegionRect(Element* aElement, nsRect& aRect)
 {

dom/canvas/CanvasRenderingContext2D.h

@@ -269,6 +269,7 @@ public:
 
   void AddHitRegion(const HitRegionOptions& options, mozilla::ErrorResult& error);
   void RemoveHitRegion(const nsAString& id);
+  void ClearHitRegions();
 
   void DrawImage(const HTMLImageOrCanvasOrVideoElement& image,
                  double dx, double dy, mozilla::ErrorResult& error)

dom/canvas/test/test_hitregion_canvas.html

@@ -33,10 +33,26 @@ function test_hitregions() {
     ctx.addHitRegion({control: e});
     ctx.addHitRegion({id: "a", control: d});
     ctx.addHitRegion({id: "a", control: d});
-    
+
     ctx.removeHitRegion("a");
     ctx.removeHitRegion("a");
     ctx.removeHitRegion("b");
+
+    ctx.clearHitRegions();
+  } catch (e) {
+      _thrown_outer = true;
+  }
+  ok(!_thrown_outer, ctx.canvas.id + ' should not throw exception');
+
+  var _thrown_outer = false;
+  try {
+    ctx.rect(10,10,100,100);
+    ctx.addHitRegion({control: d});
+    ctx.addHitRegion({control: e});
+    ctx.addHitRegion({id: "a", control: d});
+    ctx.addHitRegion({id: "a", control: d});
+
+    ctx.clearHitRegions();
   } catch (e) {
       _thrown_outer = true;
   }

dom/webidl/CanvasRenderingContext2D.webidl

@@ -125,6 +125,7 @@ interface CanvasRenderingContext2D {
   // hit regions
   [Pref="canvas.hitregions.enabled", Throws] void addHitRegion(optional HitRegionOptions options);
   [Pref="canvas.hitregions.enabled"] void removeHitRegion(DOMString id);
+  [Pref="canvas.hitregions.enabled"] void clearHitRegions();
 
   // pixel manipulation
   [NewObject, Throws]