Add GPU support for axis-aligned ovals:
- Add drawOval base function to SkDevice, and override in SkGpuDevice
- Move isSimilarityMatrix to SkMatrix (renamed to isSimilarity) and fixed up unit test
- Since both SkGpuDevice::drawOval() and GrContext::drawPath() can try to draw ovals, added GrContext::canDrawOval() and GrContext::internalDrawOval() to avoid duplicate code
- Hooked in axis-aligned oval fill shader
- Enabled GPU stroked circles
- Added stroked circle bench test

Review URL: https://codereview.appspot.com/7137050



git-svn-id: http://skia.googlecode.com/svn/trunk@7304 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/gpu/SkGpuDevice.h b/include/gpu/SkGpuDevice.h
index 45b0693..815376f 100644
--- a/include/gpu/SkGpuDevice.h
+++ b/include/gpu/SkGpuDevice.h
@@ -64,6 +64,8 @@
                             const SkPoint[], const SkPaint& paint) SK_OVERRIDE;
     virtual void drawRect(const SkDraw&, const SkRect& r,
                           const SkPaint& paint) SK_OVERRIDE;
+    virtual void drawOval(const SkDraw&, const SkRect& oval,
+                          const SkPaint& paint) SK_OVERRIDE;
     virtual void drawPath(const SkDraw&, const SkPath& path,
                           const SkPaint& paint, const SkMatrix* prePathMatrix,
                           bool pathIsMutable) SK_OVERRIDE;