Record UMA stats for Blink decoded image types

Source/platform/image-decoders/ico/ICOImageDecoder.h

 /*
  * Copyright (c) 2008, 2009, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 61 matching lines @@
         uint16_t m_bitCount;
         IntPoint m_hotSpot;
         uint32_t m_imageOffset;
     };
 
     // Returns true if |a| is a preferable icon entry to |b|.
     // Larger sizes, or greater bitdepths at the same size, are preferable.
     static bool compareEntries(const IconDirectoryEntry& a, const IconDirectoryEntry& b);
 
     // ImageDecoder:
-    virtual void decodeSize() { decode(0, true); }
+    virtual void decodeSize()
+    {
+        decode(0, true);
+        reportStats(ImageICO);

[Noel Gordon, 2015/07/30 18:11:47]

Considering that each ICO decoder has one or more child decoders, either PNG or
BMP, and those child decoders will reportStats() as well, this approach
over-counts.

Would it be possible do the counting in BitmapImage, or maybe ImageSource, to
avoid over-counting?

BitmapImage has an ImageSource which has an m_decoder, and thus an
m_decoder->filenameExtension().  Perhaps that could be used to centralize where
reportStats() is done, and not over-count?

[urvang, 2015/07/30 18:52:36]

Ah good point, thanks!
But would be have the image width and height at that point for sure? They are
needed to ignore the 1x1 images.

My initial idea was to reportStats() in ImageDecoder::Create() itself, but we
don't have width/height at that point:
https://code.google.com/p/chromium/codesearch#chromium/src/third_party/WebKit...

+    }
     size_t decodeFrameCount() override;
     void decode(size_t index) override { decode(index, false); }
 
     inline uint16_t readUint16(int offset) const
     {
         return BMPImageReader::readUint16(m_data.get(), m_decodedOffset + offset);
     }
 
     inline uint32_t readUint32(int offset) const
     {
@@ skipping 56 matching lines @@
     PNGDecoders m_pngDecoders;
 
     // Valid only while a BMPImageReader is decoding, this holds the size
     // for the particular entry being decoded.
     IntSize m_frameSize;
 };
 
 } // namespace blink
 
 #endif