Revert of Bmp Image Decoding

Revert of Bmp Image Decoding (patchset #25 id:480001 of https://codereview.chromium.org/947283002/)

Reason for revert:
breaking webkit image decoding tests

Original issue's description:
> Implementation of image decoding for bmp files, in accordance with the new API.
> 
> Currently decodes to opaque and unpremul.
> 
> Tested on local test suite.
> 
> BUG=skia:3257
> 
> Committed: https://skia.googlesource.com/skia/+/3675874468de7228944ce21922e6ec863f5f2310

TBR=scroggo@google.com,djsollen@google.com,msarett@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3257

[egdaniel, 2015-03-16 17:51:30]

Created Revert of Bmp Image Decoding

[commit-bot: I haz the power, 2015-03-16 17:51:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1010813003/1

[commit-bot: I haz the power, 2015-03-16 17:51:41]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-03-16 17:51:42]

Failed to apply patch for src/codec/SkCodec.cpp:
While running git apply --index -3 -p1;
  error: patch failed: src/codec/SkCodec.cpp:7
  error: repository lacks the necessary blob to fall back on 3-way merge.
  error: src/codec/SkCodec.cpp: patch does not apply

Patch:       src/codec/SkCodec.cpp
Index: src/codec/SkCodec.cpp
diff --git a/src/codec/SkCodec.cpp b/src/codec/SkCodec.cpp
index
ba1cf02c9e318f9baffb024e9a7c4dfcf00021fb..ec36bc75e94e00edd22b857b179a9033a95fe5c1
100644
--- a/src/codec/SkCodec.cpp
+++ b/src/codec/SkCodec.cpp
@@ -7,36 +7,24 @@
 
 #include "SkCodec.h"
 #include "SkData.h"
-#include "SkCodec_libbmp.h"
 #include "SkCodec_libpng.h"
 #include "SkStream.h"
-
-struct DecoderProc {
-    bool (*IsFormat)(SkStream*);
-    SkCodec* (*NewFromStream)(SkStream*);
-};
-
-static const uint32_t gNumDecoderProcs = 2;
-
-static const DecoderProc gDecoderProcs[] = {
-    { SkPngCodec::IsPng, SkPngCodec::NewFromStream },
-    { SkBmpCodec::IsBmp, SkBmpCodec::NewFromStream }
-};
 
 SkCodec* SkCodec::NewFromStream(SkStream* stream) {
     if (!stream) {
         return NULL;
     }
-    for (uint32_t i = 0; i < gNumDecoderProcs; i++) {
-        DecoderProc proc = gDecoderProcs[i];
-        const bool correctFormat = proc.IsFormat(stream);
-        if (!stream->rewind()) {
-            return NULL;
-        }
-        if (correctFormat) {
-            return proc.NewFromStream(stream);
-        }
+    SkAutoTDelete<SkStream> streamDeleter(stream);
+    const bool isPng = SkPngCodec::IsPng(stream);
+    // TODO: Avoid rewinding.
+    if (!stream->rewind()) {
+        return NULL;
     }
+    if (isPng) {
+        streamDeleter.detach();
+        return SkPngCodec::NewFromStream(stream);
+    }
+    // TODO: Check other image types.
     return NULL;
 }