Factor out a BaseContext from JsContext.

experimental/SkV8Example/BaseContext.h

Index: experimental/SkV8Example/BaseContext.h
diff --git a/experimental/SkV8Example/JsContext.h b/experimental/SkV8Example/BaseContext.h
similarity index 64%
copy from experimental/SkV8Example/JsContext.h
copy to experimental/SkV8Example/BaseContext.h
index c1466a08dda05e4cb7dc3b99dcc68865e6493c36..b7fe3815a6aedb30737ad5abbefe171451c45b2c 100644
--- a/experimental/SkV8Example/JsContext.h
+++ b/experimental/SkV8Example/BaseContext.h
@@ -7,8 +7,8 @@
  *
  */
 
-#ifndef SkV8Example_JsContext_DEFINED
-#define SkV8Example_JsContext_DEFINED
+#ifndef SkV8Example_BaseContext_DEFINED
+#define SkV8Example_BaseContext_DEFINED
 
 #include <v8.h>
 
@@ -19,18 +19,12 @@ using namespace v8;
 class SkCanvas;
 class Global;
 
-// Provides the canvas context implementation in JS, and the OnDraw() method in
-// C++ that's used to bridge from C++ to JS. Should be used in JS as:
-//
-//  function onDraw(context) {
-//    context.fillStyle="#FF0000";
-//    context.fillRect(x, y, w, h);
-//  }
-class JsContext {
+// BaseContext contains common functionality for both JsContext
+// and DisplayList.
+class BaseContext {
 public:
-    JsContext(Global* global)
+    BaseContext(Global* global)
             : fGlobal(global)
-            , fCanvas(NULL)
     {
         fFillStyle.setColor(SK_ColorBLACK);
         fFillStyle.setAntiAlias(true);
@@ -39,13 +33,21 @@ public:
         fStrokeStyle.setAntiAlias(true);
         fStrokeStyle.setStyle(SkPaint::kStroke_Style);
     }
-    ~JsContext();
+    virtual ~BaseContext() {}
 
-    // Parse the script.
-    bool initialize();
+    // Retrieve the SkCanvas to draw on. May return NULL.
+    virtual SkCanvas* getCanvas() = 0;
 
-    // Call this with the SkCanvas you want onDraw to draw on.
-    void onDraw(SkCanvas* canvas);
+    // Add the Javascript attributes and methods that BaseContext implements to the ObjectTemplate.
+    void addAttributesAndMethods(Handle<ObjectTemplate> tmpl);
+
+protected:
+    // Get the pointer out of obj.
+    static BaseContext* Unwrap(Handle<Object> obj);
+
+    Global* fGlobal;
+    SkPaint fFillStyle;
+    SkPaint fStrokeStyle;
 
 private:
     static void GetStyle(Local<String> name,
@@ -77,31 +79,6 @@ private:
     static void Restore(const v8::FunctionCallbackInfo<Value>& args);
     static void Translate(const v8::FunctionCallbackInfo<Value>& args);
     static void ResetTransform(const v8::FunctionCallbackInfo<Value>& args);
-
-    // Get the pointer out of obj.
-    static JsContext* Unwrap(Handle<Object> obj);
-
-    // Create a template for JS object associated with JsContext, called lazily
-    // by Wrap() and the results are stored in gContextTemplate;
-    Handle<ObjectTemplate> makeContextTemplate();
-
-    // Wrap the 'this' pointer into an Object. Can be retrieved via Unwrap.
-    Handle<Object> wrap();
-
-    Global* fGlobal;
-
-    // Only valid when inside OnDraw().
-    SkCanvas* fCanvas;
-
-    SkPaint fFillStyle;
-    SkPaint fStrokeStyle;
-
-    // A handle to the onDraw function defined in the script.
-    Persistent<Function> fOnDraw;
-
-    // The template for what a canvas context object looks like. The canvas
-    // context object is what's passed into the JS onDraw() function.
-    static Persistent<ObjectTemplate> gContextTemplate;
 };
 
 #endif