Use SkPngEncoder and SkWebpEncoder in WebKit platform

third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h

Index: third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h
diff --git a/third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h b/third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h
index b33e72deead2f37e50780ab36ea4c45541e87cc7..819fd6bc5bbd21dbe5c16f614483e14b2834abe0 100644
--- a/third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h
+++ b/third_party/WebKit/Source/platform/image-encoders/ImageEncoder.h
@@ -10,6 +10,7 @@
 #include "third_party/skia/include/core/SkStream.h"
 #include "third_party/skia/include/encode/SkJpegEncoder.h"
 #include "third_party/skia/include/encode/SkPngEncoder.h"
+#include "third_party/skia/include/encode/SkWebpEncoder.h"
 
 namespace blink {
 
@@ -42,6 +43,10 @@ class PLATFORM_EXPORT ImageEncoder {
                      const SkPixmap& src,
                      const SkPngEncoder::Options&);
 
+  static bool Encode(Vector<unsigned char>* dst,
+                     const SkPixmap& src,
+                     const SkWebpEncoder::Options&);
+
   static std::unique_ptr<ImageEncoder> Create(Vector<unsigned char>* dst,
                                               const SkPixmap& src,
                                               const SkJpegEncoder::Options&);
@@ -56,10 +61,25 @@ class PLATFORM_EXPORT ImageEncoder {
    *  If quality is in [0, 1], this will simply convert to a [0, 100]
    *  integer scale (which is what is used by libjpeg-turbo).
    *
-   *  Otherwise, this will return the default value.
+   *  Otherwise, this will return the default value (92).
    */
   static int ComputeJpegQuality(double quality);
 
+  /**
+   *  Sets Skia encoding options based on the requested quality.
+   *
+   *  If quality is 1, this will signal a lossless encode.
+   *
+   *  Otherwise, this will use webp lossy encoding.
+   *  If quality is in [0, 1), this will simply convert to a [0, 100)
+   *  float scale (which is what is used by libwebp).  If the quality
+   *  is out of range, this will perform a lossy encode with the default
+   *  value (80).
+   */
+  static SkWebpEncoder::Options ComputeWebpOptions(
+      double quality,
+      SkTransferFunctionBehavior unpremulBehavior);
+
  private:
   ImageEncoder(Vector<unsigned char>* dst) : dst_(dst) {}