Revert of Teach Skia to use discardable memory

Source/platform/graphics/DeferredImageDecoder.cpp

Index: Source/platform/graphics/DeferredImageDecoder.cpp
diff --git a/Source/platform/graphics/DeferredImageDecoder.cpp b/Source/platform/graphics/DeferredImageDecoder.cpp
index 17567e564e6fb6b0a40842c866dacb7bd4bd4cca..795ade041e30a4c8ec8f75eb7a9d4580cd97d5d1 100644
--- a/Source/platform/graphics/DeferredImageDecoder.cpp
+++ b/Source/platform/graphics/DeferredImageDecoder.cpp
@@ -26,9 +26,8 @@
 #include "config.h"
 #include "platform/graphics/DeferredImageDecoder.h"
 
-#include "platform/graphics/DecodingImageGenerator.h"
 #include "platform/graphics/LazyDecodingPixelRef.h"
-#include "third_party/skia/include/core/SkImageInfo.h"
+
 #include "wtf/PassOwnPtr.h"
 
 namespace WebCore {
@@ -38,13 +37,9 @@
 // URI label for a lazily decoded SkPixelRef.
 const char labelLazyDecoded[] = "lazy";
 
-// URI label for SkDiscardablePixelRef.
-const char labelDiscardable[] = "discardable";
-
 } // namespace
 
 bool DeferredImageDecoder::s_enabled = false;
-bool DeferredImageDecoder::s_skiaDiscardableMemoryEnabled = false;
 
 DeferredImageDecoder::DeferredImageDecoder(PassOwnPtr<ImageDecoder> actualDecoder)
     : m_allDataReceived(false)
@@ -73,18 +68,12 @@
 {
     return bitmap.pixelRef()
         && bitmap.pixelRef()->getURI()
-        && (!memcmp(bitmap.pixelRef()->getURI(), labelLazyDecoded, sizeof(labelLazyDecoded))
-            || !memcmp(bitmap.pixelRef()->getURI(), labelDiscardable, sizeof(labelDiscardable)));
+        && !memcmp(bitmap.pixelRef()->getURI(), labelLazyDecoded, sizeof(labelLazyDecoded));
 }
 
 void DeferredImageDecoder::setEnabled(bool enabled)
 {
     s_enabled = enabled;
-}
-
-void DeferredImageDecoder::setSkiaDiscardableMemoryEnabled(bool enabled)
-{
-    s_skiaDiscardableMemoryEnabled = enabled;
 }
 
 String DeferredImageDecoder::filenameExtension() const
@@ -219,7 +208,7 @@
     m_lazyDecodedFrames.resize(m_actualDecoder->frameCount());
     for (size_t i = previousSize; i < m_lazyDecodedFrames.size(); ++i) {
         OwnPtr<ImageFrame> frame(adoptPtr(new ImageFrame()));
-        frame->setSkBitmap(createBitmap(i));
+        frame->setSkBitmap(createLazyDecodingBitmap(i));
         frame->setDuration(m_actualDecoder->frameDurationAtIndex(i));
         frame->setStatus(m_actualDecoder->frameIsCompleteAtIndex(i) ? ImageFrame::FrameComplete : ImageFrame::FramePartial);
         m_lazyDecodedFrames[i] = frame.release();
@@ -235,36 +224,6 @@
         m_actualDecoder.clear();
         m_data = nullptr;
     }
-}
-
-// Creates either a SkBitmap backed by SkDiscardablePixelRef or a SkBitmap using the
-// legacy LazyDecodingPixelRef.
-SkBitmap DeferredImageDecoder::createBitmap(size_t index)
-{
-    // This code is temporary until the transition to SkDiscardablePixelRef is complete.
-    if (s_skiaDiscardableMemoryEnabled)
-        return createSkiaDiscardableBitmap(index);
-    return createLazyDecodingBitmap(index);
-}
-
-// Creates a SkBitmap that is backed by SkDiscardablePixelRef.
-SkBitmap DeferredImageDecoder::createSkiaDiscardableBitmap(size_t index)
-{
-    IntSize decodedSize = m_actualDecoder->decodedSize();
-    ASSERT(decodedSize.width() > 0);
-    ASSERT(decodedSize.height() > 0);
-
-    SkImageInfo info;
-    info.fWidth = decodedSize.width();
-    info.fHeight = decodedSize.height();
-    info.fColorType = kBGRA_8888_SkColorType;
-    info.fAlphaType = frameHasAlphaAtIndex(index) ? kPremul_SkAlphaType : kOpaque_SkAlphaType;
-
-    SkBitmap bitmap;
-    bool installed = SkInstallDiscardablePixelRef(new DecodingImageGenerator(m_frameGenerator, info, index), &bitmap);
-    ASSERT_UNUSED(installed, installed);
-    bitmap.pixelRef()->setURI(labelDiscardable);
-    return bitmap;
 }
 
 SkBitmap DeferredImageDecoder::createLazyDecodingBitmap(size_t index)