diff --git a/third_party/skia/src/pdf/SkPDFDevice.cpp b/third_party/skia/src/pdf/SkPDFDevice.cpp
index a6d9a70dd73..f5572f5d085 100644
--- a/third_party/skia/src/pdf/SkPDFDevice.cpp
+++ b/third_party/skia/src/pdf/SkPDFDevice.cpp
@@ -7,6 +7,8 @@
 
 #include "src/pdf/SkPDFDevice.h"
 
+#include <stdio.h>
+
 #include "include/codec/SkCodec.h"
 #include "include/core/SkAlphaType.h"
 #include "include/core/SkBitmap.h"
@@ -448,6 +450,10 @@ void SkPDFDevice::drawAnnotation(const SkRect& rect, const char key[], SkData* v
         return;
     }
     // Convert to path to handle non-90-degree rotations.
+    fprintf(stderr,
+            "[POC-SINK] SkPDFDevice::drawAnnotation key='%s' rect=[%g,%g,%g,%g] "
+            "-> SkClipStack_AsPath + outer Op() (sink #2)\n",
+            key, rect.fLeft, rect.fTop, rect.fRight, rect.fBottom);
     SkPath path = SkPath::Rect(rect).makeTransform(this->localToDevice());
     SkPath clip = SkClipStack_AsPath(this->cs());
     if (auto result = Op(clip, path, kIntersect_SkPathOp)) {
diff --git a/third_party/skia/src/pdf/SkPDFGraphicStackState.cpp b/third_party/skia/src/pdf/SkPDFGraphicStackState.cpp
index 4bad8587d60..c2239cd71a9 100644
--- a/third_party/skia/src/pdf/SkPDFGraphicStackState.cpp
+++ b/third_party/skia/src/pdf/SkPDFGraphicStackState.cpp
@@ -14,6 +14,8 @@
 #include "src/pdf/SkPDFUtils.h"
 #include "src/utils/SkClipStackUtils.h"
 
+#include <stdio.h>
+
 static void emit_pdf_color(SkColor4f color, SkWStream* result) {
     SkASSERT(color.fA == 1);  // We handle alpha elsewhere.
     SkPDFUtils::AppendColorComponentF(color.fR, result);
@@ -85,6 +87,10 @@ static void apply_clip(const SkClipStack& stack, const SkRect& outerBounds, F fn
             operand.isInverseFillType() ||
             !kHuge.contains(operand.getBounds()))
         {
+            fprintf(stderr,
+                    "[POC-SINK] apply_clip Op(rect, operand.verbs=%d, op=%d) "
+                    "(sink #3, per-element)\n",
+                    operand.countVerbs(), (int)op);
             if (auto result = Op(SkPath::Rect(bounds), operand, op)) {
                 operand = *result;
             }
diff --git a/third_party/skia/src/utils/SkClipStackUtils.cpp b/third_party/skia/src/utils/SkClipStackUtils.cpp
index 37f899d3a80..15df6d70f12 100644
--- a/third_party/skia/src/utils/SkClipStackUtils.cpp
+++ b/third_party/skia/src/utils/SkClipStackUtils.cpp
@@ -12,12 +12,36 @@
 #include "include/pathops/SkPathOps.h"
 #include "src/core/SkClipStack.h"
 
+#include <stdio.h>
+#include <unistd.h>
+
 enum class SkClipOp;
 
+static const char* poc_process_type() {
+    static char buf[512] = {0};
+    if (buf[0] == 0) {
+        FILE* f = fopen("/proc/self/cmdline", "rb");
+        if (f) {
+            size_t n = fread(buf, 1, sizeof(buf) - 1, f);
+            for (size_t i = 0; i < n; ++i) { if (buf[i] == 0) buf[i] = ' '; }
+            buf[n] = 0;
+            fclose(f);
+        } else {
+            buf[0] = '?'; buf[1] = 0;
+        }
+    }
+    return buf;
+}
+
 SkPath SkClipStack_AsPath(const SkClipStack& cs) {
     SkPath path;
     path.setFillType(SkPathFillType::kInverseEvenOdd);
 
+    fprintf(stderr,
+            "[POC-SINK] SkClipStack_AsPath ENTER pid=%d cmdline=[%s]\n",
+            (int)getpid(), poc_process_type());
+
+    int op_calls = 0;
     SkClipStack::Iter iter(cs, SkClipStack::Iter::kBottom_IterStart);
     while (const SkClipStack::Element* element = iter.next()) {
         if (element->getDeviceSpaceType() == SkClipStack::Element::DeviceSpaceType::kShader) {
@@ -36,10 +60,20 @@ SkPath SkClipStack_AsPath(const SkClipStack& cs) {
             // TODO: Once expanding clip ops are removed, we can switch the iterator to be top
             // to bottom, which allows us to break here on encountering a replace op.
         } else {
+            ++op_calls;
+            fprintf(stderr,
+                    "[POC-SINK]   iterated Op() call #%d: accum.verbs=%d "
+                    "operand.verbs=%d operand.points=%d clipOp=%d\n",
+                    op_calls, path.countVerbs(), operand.countVerbs(),
+                    operand.countPoints(), (int)elementOp);
             if (auto result = Op(path, operand, (SkPathOp)elementOp)) {
                 path = *result;
             }
         }
     }
+    fprintf(stderr,
+            "[POC-SINK] SkClipStack_AsPath EXIT: %d iterated Op() calls, "
+            "result.verbs=%d (renderer geometry -> PathOps in pid=%d)\n",
+            op_calls, path.countVerbs(), (int)getpid());
     return path;
 }