cc: Add PaintShader debug printing

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I70ee24b28189726254ea22798054d48d5b8a2706
Reviewed-on: https://chromium-review.googlesource.com/1112722
Commit-Queue: enne <enne@chromium.org>
Commit-Queue: Khushal <khushalsagar@chromium.org>
Reviewed-by: Khushal <khushalsagar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569864}

cc/paint/paint_shader.h

@@ -159,6 +159,7 @@ class CC_PAINT_EXPORT PaintShader : public SkRefCnt {
 
  private:
   friend class PaintFlags;
+  friend class PaintOpHelper;
   friend class PaintOpReader;
   friend class PaintOpSerializationTestUtils;
   friend class PaintOpWriter;

cc/test/paint_op_helper.h

@@ -219,6 +219,10 @@ class PaintOpHelper {
     return base::StringPrintf("%.3f", scalar);
   }
 
+  static std::string SkiaTypeToString(const SkPoint& point) {
+    return base::StringPrintf("[%.3f,%.3f]", point.fX, point.fY);
+  }
+
   static std::string SkiaTypeToString(const SkRect& rect) {
     return base::StringPrintf("[%.3f,%.3f %.3fx%.3f]", rect.x(), rect.y(),
                               rect.width(), rect.height());
@@ -469,6 +473,16 @@ class PaintOpHelper {
     return "<unknown SrcRectConstraint>";
   }
 
+  static std::string EnumToString(PaintShader::ScalingBehavior behavior) {
+    switch (behavior) {
+      case PaintShader::ScalingBehavior::kRasterAtScale:
+        return "kRasterAtScale";
+      case PaintShader::ScalingBehavior::kFixedScale:
+        return "kFixedScale";
+    }
+    return "<unknown ScalingBehavior>";
+  }
+
   static std::string ImageToString(const PaintImage& image) {
     return "<paint image>";
   }
@@ -483,7 +497,57 @@ class PaintOpHelper {
   }
 
   static std::string PaintShaderToString(const PaintShader* shader) {
-    return shader ? "<PaintShader>" : "(nil)";
+    if (!shader)
+      return "(nil)";
+    std::ostringstream str;
+    str << "[flags=" << shader->flags_;
+    str << ", end_radius=" << shader->end_radius_;
+    str << ", start_radius=" << shader->start_radius_;
+    str << ", tx=" << shader->tx_;
+    str << ", ty=" << shader->ty_;
+    str << ", fallback_color=" << shader->fallback_color_;
+    str << ", scaling_behavior=" << EnumToString(shader->scaling_behavior_);
+    if (shader->local_matrix_.has_value()) {
+      str << ", local_matrix=" << SkiaTypeToString(*shader->local_matrix_);
+    } else {
+      str << ", local_matrix=(nil)";
+    }
+    str << ", center=" << SkiaTypeToString(shader->center_);
+    str << ", tile=" << SkiaTypeToString(shader->tile_);
+    str << ", start_point=" << SkiaTypeToString(shader->start_point_);
+    str << ", end_point=" << SkiaTypeToString(shader->end_point_);
+    str << ", start_degrees=" << shader->start_degrees_;
+    str << ", end_degrees=" << shader->end_degrees_;
+    str << ", image=" << ImageToString(shader->image_);
+    str << ", record=" << RecordToString(shader->record_);
+    str << ", id=" << shader->id_;
+    str << ", tile_scale=";
+    if (shader->tile_scale_) {
+      str << "[" << shader->tile_scale_->ToString() << "]";
+    } else {
+      str << "(nil)";
+    }
+    if (shader->colors_.size() > 0) {
+      str << ", colors=[" << shader->colors_[0];
+      for (size_t i = 1; i < shader->colors_.size(); ++i) {
+        str << ", " << shader->colors_[i];
+      }
+      str << "]";
+    } else {
+      str << ", colors=(nil)";
+    }
+    if (shader->positions_.size() > 0) {
+      str << ", positions=[" << shader->positions_[0];
+      for (size_t i = 1; i < shader->positions_.size(); ++i) {
+        str << ", " << shader->positions_[i];
+      }
+      str << "]";
+    } else {
+      str << ", positions=(nil)";
+    }
+    str << "]";
+
+    return str.str();
   }
 
   static std::string PaintFilterToString(const sk_sp<PaintFilter> filter) {