add optional Format* parameter to decoder helper functions.



git-svn-id: http://skia.googlecode.com/svn/trunk@215 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/images/SkImageDecoder.cpp b/src/images/SkImageDecoder.cpp
index b910df6..4f9fa9b 100644
--- a/src/images/SkImageDecoder.cpp
+++ b/src/images/SkImageDecoder.cpp
@@ -120,13 +120,13 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 bool SkImageDecoder::DecodeFile(const char file[], SkBitmap* bm,
-                                SkBitmap::Config pref,  Mode mode) {
+                            SkBitmap::Config pref,  Mode mode, Format* format) {
     SkASSERT(file);
     SkASSERT(bm);
 
     SkFILEStream    stream(file);
     if (stream.isValid()) {
-        if (SkImageDecoder::DecodeStream(&stream, bm, pref, mode)) {
+        if (SkImageDecoder::DecodeStream(&stream, bm, pref, mode, format)) {
             bm->pixelRef()->setURI(file);
         }
         return true;
@@ -135,18 +135,18 @@
 }
 
 bool SkImageDecoder::DecodeMemory(const void* buffer, size_t size, SkBitmap* bm,
-                                  SkBitmap::Config pref, Mode mode) {
+                          SkBitmap::Config pref, Mode mode, Format* format) {
     if (0 == size) {
         return false;
     }
     SkASSERT(buffer);
 
     SkMemoryStream  stream(buffer, size);
-    return SkImageDecoder::DecodeStream(&stream, bm, pref, mode);
+    return SkImageDecoder::DecodeStream(&stream, bm, pref, mode, format);
 }
 
 bool SkImageDecoder::DecodeStream(SkStream* stream, SkBitmap* bm,
-                                  SkBitmap::Config pref, Mode mode) {
+                          SkBitmap::Config pref, Mode mode, Format* format) {
     SkASSERT(stream);
     SkASSERT(bm);
 
@@ -155,6 +155,9 @@
 
     if (NULL != codec) {
         success = codec->decode(stream, bm, pref, mode);
+        if (success && format) {
+            *format = codec->getFormat();
+        }
         delete codec;
     }
     return success;