[devtools] Support different encodings for Page.CaptureScreenshot.

ui/gfx/image/image_util.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_GFX_IMAGE_IMAGE_UTIL_H_
 #define UI_GFX_IMAGE_IMAGE_UTIL_H_
 
 #include <stddef.h>
 
 #include <vector>
@@ skipping 15 matching lines @@
 // Fills the |dst| vector with JPEG-encoded bytes of the 1x representation of
 // the given image.
 // Returns true if the image has a 1x representation and the 1x representation
 // was encoded successfully.
 // |quality| determines the compression level, 0 == lowest, 100 == highest.
 // Returns true if the Image was encoded successfully.
 GFX_EXPORT bool JPEG1xEncodedDataFromImage(const Image& image,
                                            int quality,
                                            std::vector<unsigned char>* dst);
 
+bool JPEG1xEncodedDataFromSkiaRepresentation(const Image& image,

[Avi (use Gerrit), 2017/01/09 16:57:33]

GFX_EXPORT?

[Avi (use Gerrit), 2017/01/09 22:59:57]

Ah, I see, this is for internal use only. Never mind.

+                                             int quality,
+                                             std::vector<unsigned char>* dst);
+
 // Computes the width of any nearly-transparent regions at the sides of the
 // image and returns them in |left| and |right|.  This checks each column of
 // pixels from the outsides in, looking for anything with alpha above a
 // reasonably small value.  For a fully-opaque image, the margins will thus be
 // (0, 0); for a fully-transparent image, the margins will be
 // (width / 2, width / 2), with |left| getting the extra pixel for odd widths.
 GFX_EXPORT void GetVisibleMargins(const ImageSkia& image,
                                   int* left,
                                   int* right);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_IMAGE_IMAGE_UTIL_H_