Updates to skimage tool to use it for testing.

include/images/SkImageDecoder.h

Index: include/images/SkImageDecoder.h
diff --git a/include/images/SkImageDecoder.h b/include/images/SkImageDecoder.h
index 38e77f4df765e7139f0f2507f57fbd4e0c00ae23..47e8a7b426dd5c4a4b3f7ead064614582426d02d 100644
--- a/include/images/SkImageDecoder.h
+++ b/include/images/SkImageDecoder.h
@@ -26,7 +26,6 @@ class SkImageDecoder {
 public:
     virtual ~SkImageDecoder();
 
-    // Should be consistent with sFormatName
     enum Format {
         kUnknown_Format,
         kBMP_Format,
@@ -37,14 +36,20 @@ public:
         kWBMP_Format,
         kWEBP_Format,
 
-        kLastKnownFormat = kWEBP_Format
+        kLastKnownFormat = kWEBP_Format,
+        kMultiple_Formats,

[scroggo, 2013/04/22 22:10:16]

Does this seem like the right place for kMultiple_Formats?

[epoger, 2013/04/23 16:03:41]

This seems problematic to me.  Maybe, instead, there could be a bool
decodesFormat(Format f) method that tells the caller whether a particular format
is supported?  The caller can loop through and try several if he wants to...

Otherwise, return an array of formats that are supported.

[scroggo, 2013/04/24 18:00:05]

That seems reasonable to me. For now though, I'll leave getFormat the way it is
and look into deprecation in a further CL.

     };
 
     /** Return the format of image this decoder can decode. If this decoder can decode multiple
-        formats, kUnknown_Format will be returned.
+        formats, returns kMultiple_Formats.
     */
     virtual Format getFormat() const;
 
+    /** If this decoder can determine the format of stream, return its format. Otherwise return
+        kUnknown_Format.

[epoger, 2013/04/23 16:03:41]

Please indicate what state the SkStream will be left in (fully rewound? unknown
state?)

[scroggo, 2013/04/24 18:00:05]

Done.

+    */
+    Format getFormat(SkStream*) const;
+
     /** Return a readable string of the value returned by getFormat().
     */
     const char* getFormatName() const;

[scroggo, 2013/04/22 22:10:16]

Derek, does Android call this? (I assume I have access now so I can check?)

I'm tempted to deprecate it in favor of a function which takes an
SkImageDecoder::Format instead.

[djsollen, 2013/04/23 16:40:46]

It is only used in a debug statement in the BitmapRegionDecoder.cpp

@@ -329,6 +334,10 @@ public:
     static void SetDeviceConfig(SkBitmap::Config);
 
 protected:
+    // Override this in subclass to read a stream and determine its format.
+    // No need to rewind the stream, which will be handled in getFormat.
+    virtual Format onGetFormat(SkStream*) const;
+
     // must be overridden in subclasses. This guy is called by decode(...)
     virtual bool onDecode(SkStream*, SkBitmap* bitmap, Mode) = 0;
 
@@ -416,13 +425,6 @@ private:
     mutable bool            fShouldCancelDecode;
     bool                    fPreferQualityOverSpeed;
 
-    /** Contains the image format name.
-     *  This should be consistent with Format.
-     *
-     *  The format name gives a more meaningful error message than enum.
-     */
-    static const char* sFormatName[];
-
     // illegal
     SkImageDecoder(const SkImageDecoder&);
     SkImageDecoder& operator=(const SkImageDecoder&);