add pipecanvas

include/core/SkWriteBuffer.h

Index: include/core/SkWriteBuffer.h
diff --git a/include/core/SkWriteBuffer.h b/include/core/SkWriteBuffer.h
index 87ac8bf21494aa3ea8ec2aec7823a03bf74a0bea..83af4419ba00f2113c6ac1fbbe9bb49ff8b37727 100644
--- a/include/core/SkWriteBuffer.h
+++ b/include/core/SkWriteBuffer.h
@@ -19,6 +19,7 @@
 #include "../private/SkTHash.h"
 
 class SkBitmap;
+class SkDeduper;
 class SkFactorySet;
 class SkFlattenable;
 class SkRefCntSet;
@@ -30,6 +31,8 @@ public:
 
     virtual bool isCrossProcess() const = 0;
 
+    virtual void write(const void*, size_t) { sk_throw(); }

[mtklein, 2016/08/04 12:50:37]

The other implementation of SkWriteBuffer isn't writing bytes, so I don't think
it'll ever be able to be implemented.

Why don't we just keep it non-virtual on SkBinaryWriteBuffer?

[reed1, 2016/08/04 13:18:41]

Makes sense. I hadn't internalized that I was going to require that my writer be
a subclass of BinaryWriter, but of course it will be.

+
     virtual void writeByteArray(const void* data, size_t size) = 0;
     void writeDataAsByteArray(SkData* data) {
         this->writeByteArray(data->data(), data->size());
@@ -60,12 +63,24 @@ public:
     virtual void writeImage(const SkImage*) = 0;
     virtual void writeTypeface(SkTypeface* typeface) = 0;
     virtual void writePaint(const SkPaint& paint) = 0;
+
+    void setDedupers(SkDeduper* images, SkDeduper* typefaces) {

[mtklein, 2016/08/04 12:50:37]

We can probably just put these on SkBinaryWriteBuffer too?

+        fImageDeduper = images;
+        fTypefaceDeduper = typefaces;
+    }
+
+protected:
+    bool newWriteImage(const SkImage*);
+    bool newWriteTypeface(SkTypeface*);
+
+    SkDeduper*  fImageDeduper = nullptr;
+    SkDeduper*  fTypefaceDeduper = nullptr;
 };
 
 /**
  * Concrete implementation that serializes to a flat binary blob.
  */
-class SkBinaryWriteBuffer final : public SkWriteBuffer {
+class SkBinaryWriteBuffer : public SkWriteBuffer {
 public:
     enum Flags {
         kCrossProcess_Flag = 1 << 0,
@@ -79,6 +94,10 @@ public:
         return SkToBool(fFlags & kCrossProcess_Flag);
     }
 
+    void write(const void* buffer, size_t bytes) override {
+        fWriter.write(buffer, bytes);
+    }
+
     void reset(void* storage = NULL, size_t storageSize = 0) {
         fWriter.reset(storage, storageSize);
     }