Support rrect clips in analysis canvas

skia/ext/analysis_canvas.cc

Index: skia/ext/analysis_canvas.cc
diff --git a/skia/ext/analysis_canvas.cc b/skia/ext/analysis_canvas.cc
index 2caa73d00dd2cbad35493532d6de1b9ade8cd84d..c6c1802a4da1946cb7b3bd46203c19b8d10e5970 100644
--- a/skia/ext/analysis_canvas.cc
+++ b/skia/ext/analysis_canvas.cc
@@ -410,9 +410,41 @@ void AnalysisCanvas::onClipPath(const SkPath& path,
   INHERITED::onClipRect(path.getBounds(), op, edge_style);
 }
 
+bool doesCoverCanvas(const SkRRect& rr,
+                     const SkMatrix& total_matrix,
+                     const SkIRect& clip_device_bounds) {
+  const SkRect& bounding_rect = rr.rect();
+
+  // We cannot handle non axis aligned rectangles at the moment.
+  if (!total_matrix.isScaleTranslate()) {
+    return false;
+  }
+
+  SkMatrix inverse;
+  if (!total_matrix.invert(&inverse)) {
+    return false;
+  }
+
+  SkRect clip_rect = SkRect::MakeFromIRect(clip_device_bounds);

[f(malita), 2016/10/26 12:24:24]

nit: MakeFromIRect is deprecated, you can use Make().

[Ian Vollick, 2016/10/26 13:57:04]

Done.

+  inverse.mapRectScaleTranslate(&clip_rect, clip_rect);
+  if (!clip_rect.isFinite()) {

[f(malita), 2016/10/26 12:24:24]

nit: Is this check needed?  I think the contains test below would cover this
case too.

[Ian Vollick, 2016/10/26 13:57:04]

Nope, not necessary. Removed.

+    return false;
+  }
+
+  return rr.contains(clip_rect);
+}
+
 void AnalysisCanvas::onClipRRect(const SkRRect& rrect,
                                  SkRegion::Op op,
                                  ClipEdgeStyle edge_style) {
+  SkIRect clip_device_bounds;
+  if (getClipDeviceBounds(&clip_device_bounds) &&
+      doesCoverCanvas(rrect, getTotalMatrix(), clip_device_bounds)) {
+    // If the canvas is fully contained within the clip, it is as if we weren't
+    // clipped at all, so bail early.
+    return;
+  }
+
   OnComplexClip();
   INHERITED::onClipRect(rrect.getBounds(), op, edge_style);
 }