Add dedicated Read/Write overrides for SkTileMode

This simplification was requested as part of feedback to:
https://chromium-review.googlesource.com/c/chromium/src/+/2527768

Bug: skia:9310
Change-Id: I487d38decc258201767e8a7849f1051ced983163
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2600380Reviewed-by: danakj <danakj@chromium.org>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
Cr-Commit-Position: refs/heads/master@{#839642}

cc/paint/paint_op_reader.cc

@@ -41,18 +41,6 @@ bool IsValidPaintShaderType(PaintShader::Type type) {
          static_cast<uint8_t>(PaintShader::Type::kShaderCount);
 }
 
-// SkTileMode has no defined backing type, so read/write int32_t's.
-// If read_mode is a valid tile mode, this returns true and updates mode to the
-// equivalent enum value. Otherwise false is returned and mode is not modified.
-bool ValidateAndGetSkShaderTileMode(int32_t read_mode, SkTileMode* mode) {
-  if (read_mode < 0 || read_mode >= kSkTileModeCount) {
-    return false;
-  }
-
-  *mode = static_cast<SkTileMode>(read_mode);
-  return true;
-}
-
 bool IsValidPaintShaderScalingBehavior(PaintShader::ScalingBehavior behavior) {
   return behavior == PaintShader::ScalingBehavior::kRasterAtScale ||
          behavior == PaintShader::ScalingBehavior::kFixedScale;
@@ -523,16 +511,8 @@ void PaintOpReader::Read(sk_sp<PaintShader>* shader) {
   ReadSimple(&ref.flags_);
   ReadSimple(&ref.end_radius_);
   ReadSimple(&ref.start_radius_);
-
-  // See ValidateAndGetSkShaderTileMode
-  int32_t tx = 0;
-  int32_t ty = 0;
-  Read(&tx);
-  Read(&ty);
-  if (!ValidateAndGetSkShaderTileMode(tx, &ref.tx_) ||
-      !ValidateAndGetSkShaderTileMode(ty, &ref.ty_)) {
-    SetInvalid();
-  }
+  Read(&ref.tx_);
+  Read(&ref.ty_);
   ReadSimple(&ref.fallback_color_);
   ReadSimple(&ref.scaling_behavior_);
   if (!IsValidPaintShaderScalingBehavior(ref.scaling_behavior_))

cc/paint/paint_op_reader.h

@@ -117,6 +117,15 @@ class CC_PAINT_EXPORT PaintOpReader {
     }
     *blend_mode = static_cast<SkBlendMode>(value);
   }
+  void Read(SkTileMode* tile_mode) {
+    uint8_t value = 0u;
+    Read(&value);
+    if (value >= kSkTileModeCount) {
+      SetInvalid();
+      return;
+    }
+    *tile_mode = static_cast<SkTileMode>(value);
+  }
   void Read(bool* data) {
     uint8_t value = 0u;
     Read(&value);

cc/paint/paint_op_writer.cc

@@ -480,10 +480,8 @@ void PaintOpWriter::Write(const PaintShader* shader, SkFilterQuality quality) {
   WriteSimple(shader->flags_);
   WriteSimple(shader->end_radius_);
   WriteSimple(shader->start_radius_);
-  // SkTileMode does not have an explicitly defined backing type, so
-  // write a consistently sized value.
-  Write(static_cast<int32_t>(shader->tx_));
-  Write(static_cast<int32_t>(shader->ty_));
+  Write(shader->tx_);
+  Write(shader->ty_);
   WriteSimple(shader->fallback_color_);
   WriteSimple(shader->scaling_behavior_);
   if (shader->local_matrix_) {

cc/paint/paint_op_writer.h

@@ -88,6 +88,7 @@ class CC_PAINT_EXPORT PaintOpWriter {
   void Write(SkBlendMode blend_mode) {
     Write(static_cast<uint8_t>(blend_mode));
   }
+  void Write(SkTileMode tile_mode) { Write(static_cast<uint8_t>(tile_mode)); }
   void Write(bool data) { Write(static_cast<uint8_t>(data)); }
 
   // Aligns the memory to the given alignment.