IDL: make optional arguments (without default) explicit sometimes

Source/core/html/canvas/CanvasRenderingContext2D.h

Index: Source/core/html/canvas/CanvasRenderingContext2D.h
diff --git a/Source/core/html/canvas/CanvasRenderingContext2D.h b/Source/core/html/canvas/CanvasRenderingContext2D.h
index 6eba5f5b313772a10a5e9c24f1d7f6c3be305281..5cf23ca897114e8a231605427d67a96bd81730b5 100644
--- a/Source/core/html/canvas/CanvasRenderingContext2D.h
+++ b/Source/core/html/canvas/CanvasRenderingContext2D.h
@@ -26,6 +26,7 @@
 #ifndef CanvasRenderingContext2D_h
 #define CanvasRenderingContext2D_h
 
+#include "bindings/core/v8/Optional.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/css/CSSFontSelectorClient.h"
 #include "core/html/canvas/Canvas2DContextAttributes.h"
@@ -134,16 +135,12 @@ public:
     void setTransform(float m11, float m12, float m21, float m22, float dx, float dy);
     void resetTransform();
 
-    void setStrokeColor(const String& color);
-    void setStrokeColor(float grayLevel);
-    void setStrokeColor(const String& color, float alpha);
+    void setStrokeColor(const String& color, Optional<float> alpha);
     void setStrokeColor(float grayLevel, float alpha);
     void setStrokeColor(float r, float g, float b, float a);
     void setStrokeColor(float c, float m, float y, float k, float a);
 
-    void setFillColor(const String& color);
-    void setFillColor(float grayLevel);
-    void setFillColor(const String& color, float alpha);
+    void setFillColor(const String& color, Optional<float> alpha);
     void setFillColor(float grayLevel, float alpha);
     void setFillColor(float r, float g, float b, float a);
     void setFillColor(float c, float m, float y, float k, float a);
@@ -162,17 +159,13 @@ public:
     bool isPointInStroke(const float x, const float y);
     bool isPointInStroke(Path2D*, const float x, const float y);
 
-    void scrollPathIntoView();
     void scrollPathIntoView(Path2D*);
 
     void clearRect(float x, float y, float width, float height);
     void fillRect(float x, float y, float width, float height);
     void strokeRect(float x, float y, float width, float height);
 
-    void setShadow(float width, float height, float blur);
-    void setShadow(float width, float height, float blur, const String& color);
-    void setShadow(float width, float height, float blur, float grayLevel);
-    void setShadow(float width, float height, float blur, const String& color, float alpha);
+    void setShadow(float width, float height, float blur, const Optional<String>& color, Optional<float> alpha);
     void setShadow(float width, float height, float blur, float grayLevel, float alpha);
     void setShadow(float width, float height, float blur, float r, float g, float b, float a);
     void setShadow(float width, float height, float blur, float c, float m, float y, float k, float a);
@@ -211,10 +204,8 @@ public:
     String textBaseline() const;
     void setTextBaseline(const String&);
 
-    void fillText(const String& text, float x, float y);
-    void fillText(const String& text, float x, float y, float maxWidth);
-    void strokeText(const String& text, float x, float y);
-    void strokeText(const String& text, float x, float y, float maxWidth);
+    void fillText(const String& text, float x, float y, Optional<float> maxWidth);
+    void strokeText(const String& text, float x, float y, Optional<float> maxWidth);
     PassRefPtrWillBeRawPtr<TextMetrics> measureText(const String& text);
 
     LineCap getLineCap() const { return state().m_lineCap; }