Implement vertex buffer caching in the tessellated path renderer.

tests/PathTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkPaint.h"
 #include "SkParse.h"
@@ skipping 3660 matching lines @@
     compare_dump(reporter, p, false, true,
                  "path.moveTo(SkBits2Float(0x3f800000), SkBits2Float(0x40000000));  // 1, 2\n"
                  "path.lineTo(SkBits2Float(0x40400000), SkBits2Float(0x40800000));  // 3, 4\n");
     p.reset();
     p.moveTo(SkBits2Float(0x3f800000), SkBits2Float(0x40000000));
     p.lineTo(SkBits2Float(0x40400000), SkBits2Float(0x40800000));
     compare_dump(reporter, p, false, false, "path.moveTo(1, 2);\n"
                                             "path.lineTo(3, 4);\n");
 }
 
+namespace {
+
+class ChangeListener : public SkPathRef::GenIDChangeListener {
+public:
+    ChangeListener(bool *changed) : fChanged(changed) { *fChanged = false; }
+    virtual ~ChangeListener() {}
+    void onChange() override {
+        *fChanged = true;
+    }
+private:
+    bool* fChanged;
+};
+
+}
+
 class PathTest_Private {
 public:
     static void TestPathTo(skiatest::Reporter* reporter) {
         SkPath p, q;
         p.lineTo(4, 4);
         p.reversePathTo(q);
         check_path_is_line(reporter, &p, 4, 4);
         q.moveTo(-4, -4);
         p.reversePathTo(q);
         check_path_is_line(reporter, &p, 4, 4);
         q.lineTo(7, 8);
         q.conicTo(8, 7, 6, 5, 0.5f);
         q.quadTo(6, 7, 8, 6);
         q.cubicTo(5, 6, 7, 8, 7, 5);
         q.close();
         p.reversePathTo(q);
         SkRect reverseExpected = {-4, -4, 8, 8};
         REPORTER_ASSERT(reporter, p.getBounds() == reverseExpected);
     }
+
+    static void TestPathrefListeners(skiatest::Reporter* reporter) {
+        SkPath p;
+
+        bool changed = false;
+        p.moveTo(0, 0);
+
+        // Check that listener is notified on moveTo().
+        p.pathRef()->addGenIDChangeListener(SkNEW(ChangeListener(&changed)));
+        REPORTER_ASSERT(reporter, !changed);
+        p.moveTo(10, 0);
+        REPORTER_ASSERT(reporter, changed);
+
+        // Check that listener is notified on lineTo().
+        p.pathRef()->addGenIDChangeListener(SkNEW(ChangeListener(&changed)));
+        REPORTER_ASSERT(reporter, !changed);
+        p.lineTo(20, 0);
+        REPORTER_ASSERT(reporter, changed);
+
+        // Check that listener is notified on reset().
+        p.pathRef()->addGenIDChangeListener(SkNEW(ChangeListener(&changed)));
+        REPORTER_ASSERT(reporter, !changed);
+        p.reset();
+        REPORTER_ASSERT(reporter, changed);
+
+        p.moveTo(0, 0);
+
+        // Check that listener is notified on rewind().
+        p.pathRef()->addGenIDChangeListener(SkNEW(ChangeListener(&changed)));
+        REPORTER_ASSERT(reporter, !changed);
+        p.rewind();
+        REPORTER_ASSERT(reporter, changed);
+
+        // Check that listener is notified when pathref is deleted.
+        {
+            SkPath q;
+            q.moveTo(10, 10);
+            q.pathRef()->addGenIDChangeListener(SkNEW(ChangeListener(&changed)));
+            REPORTER_ASSERT(reporter, !changed);
+        }
+        // q went out of scope.
+        REPORTER_ASSERT(reporter, changed);
+    }
 };
 
 DEF_TEST(Paths, reporter) {
     test_path_crbug364224();
 
     SkTSize<SkScalar>::Make(3,4);
 
     SkPath  p, empty;
     SkRect  bounds, bounds2;
     test_empty(reporter, p);
@@ skipping 126 matching lines @@
     test_addPathMode(reporter, false, true);
     test_addPathMode(reporter, true, true);
     test_extendClosedPath(reporter);
     test_addEmptyPath(reporter, SkPath::kExtend_AddPathMode);
     test_addEmptyPath(reporter, SkPath::kAppend_AddPathMode);
     test_conicTo_special_case(reporter);
     test_get_point(reporter);
     test_contains(reporter);
     PathTest_Private::TestPathTo(reporter);
     PathRefTest_Private::TestPathRef(reporter);
+    PathTest_Private::TestPathrefListeners(reporter);
     test_dump(reporter);
     test_path_crbug389050(reporter);
     test_path_crbugskia2820(reporter);
     test_skbug_3469(reporter);
     test_skbug_3239(reporter);
 }