Implement basic parts of hit regions on canvas2d.

Source/platform/graphics/GraphicsContext.cpp

 /*
  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 20 matching lines @@
 #include "platform/geometry/IntRect.h"
 #include "platform/geometry/RoundedRect.h"
 #include "platform/graphics/BitmapImage.h"
 #include "platform/graphics/DisplayList.h"
 #include "platform/graphics/Gradient.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/text/BidiResolver.h"
 #include "platform/text/TextRunIterator.h"
 #include "platform/weborigin/KURL.h"
 #include "third_party/skia/include/core/SkAnnotation.h"
+#include "third_party/skia/include/core/SkClipStack.h"
 #include "third_party/skia/include/core/SkColorFilter.h"
 #include "third_party/skia/include/core/SkData.h"
 #include "third_party/skia/include/core/SkDevice.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/core/SkRRect.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 #include "third_party/skia/include/core/SkSurface.h"
 #include "third_party/skia/include/effects/SkBlurMaskFilter.h"
 #include "third_party/skia/include/effects/SkCornerPathEffect.h"
 #include "third_party/skia/include/effects/SkLumaColorFilter.h"
@@ skipping 1315 matching lines @@
     SkPath& path = const_cast<SkPath&>(pathToClip.skPath());
     SkPath::FillType previousFillType = path.getFillType();
 
     SkPath::FillType temporaryFillType = clipRule == RULE_EVENODD ? SkPath::kEvenOdd_FillType : SkPath::kWinding_FillType;
     path.setFillType(temporaryFillType);
     clipPath(path, AntiAliased);
 
     path.setFillType(previousFillType);
 }
 
+bool GraphicsContext::isClipMode() const
+{
+    if (contextDisabled())
+        return false;
+
+    return m_canvas->getClipStack()->getSaveCount() != 0;
+}
+
 void GraphicsContext::clipConvexPolygon(size_t numPoints, const FloatPoint* points, bool antialiased)
 {
     if (contextDisabled())
         return;
 
     if (numPoints <= 1)
         return;
 
     SkPath path;
     setPathFromConvexPoints(&path, numPoints, points);
@@ skipping 430 matching lines @@
 
 void GraphicsContext::didDrawTextInRect(const SkRect& textRect)
 {
     if (m_trackTextRegion) {
         TRACE_EVENT0("skia", "GraphicsContext::didDrawTextInRect");
         m_textRegion.join(textRect);
     }
 }
 
 }