SkPDF: properly dedup bitmaps in shaders

src/pdf/SkPDFShader.cpp

Index: src/pdf/SkPDFShader.cpp
diff --git a/src/pdf/SkPDFShader.cpp b/src/pdf/SkPDFShader.cpp
index 5dd94e2c68138317b90527b0642aece103d158ac..d6ed6632b5c23117f7e7e69f8b6f0dd2ff4140f8 100644
--- a/src/pdf/SkPDFShader.cpp
+++ b/src/pdf/SkPDFShader.cpp
@@ -430,7 +430,7 @@ public:
     SkIRect fBBox;
 
     SkBitmap fImage;
-    uint32_t fPixelGeneration;
+    SkBitmapKey fBitmapKey;
     SkShader::TileMode fImageTileModes[2];
 
     State(SkShader* shader, const SkMatrix& canvasTransform,
@@ -1046,8 +1046,8 @@ bool SkPDFShader::State::operator==(const SkPDFShader::State& b) const {
     }
 
     if (fType == SkShader::kNone_GradientType) {
-        if (fPixelGeneration != b.fPixelGeneration ||
-                fPixelGeneration == 0 ||
+        if (fBitmapKey != b.fBitmapKey ||
+                fBitmapKey.id() == 0 ||
                 fImageTileModes[0] != b.fImageTileModes[0] ||
                 fImageTileModes[1] != b.fImageTileModes[1]) {
             return false;
@@ -1093,8 +1093,7 @@ bool SkPDFShader::State::operator==(const SkPDFShader::State& b) const {
 SkPDFShader::State::State(SkShader* shader, const SkMatrix& canvasTransform,
                           const SkIRect& bbox, SkScalar rasterScale)
         : fCanvasTransform(canvasTransform),
-          fBBox(bbox),
-          fPixelGeneration(0) {
+          fBBox(bbox) {
     fInfo.fColorCount = 0;
     fInfo.fColors = nullptr;
     fInfo.fColorOffsets = nullptr;
@@ -1148,7 +1147,7 @@ SkPDFShader::State::State(SkShader* shader, const SkMatrix& canvasTransform,
             fShaderTransform.setTranslate(shaderRect.x(), shaderRect.y());
             fShaderTransform.preScale(1 / scale.width(), 1 / scale.height());
         }
-        fPixelGeneration = fImage.getGenerationID();
+        fBitmapKey = SkBitmapKey(fImage);
     } else {
         AllocateGradientInfoStorage();
         shader->asAGradient(&fInfo);