DO NOT COMMIT: Experimental removal of encoded image data

third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp

Index: third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
index 62529643b6be1c9b5f514da7ddc461abe057fa29..9b0738885104e6c9d2dba89877b152eda29d443f 100644
--- a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.cpp
@@ -87,6 +87,7 @@ DeferredImageDecoder::DeferredImageDecoder(std::unique_ptr<ImageDecoder> actualD
     , m_hasColorProfile(false)
     , m_canYUVDecode(false)
     , m_hasHotSpot(false)
+    , m_isBufferCleared(false)
 {
 }
 
@@ -128,6 +129,15 @@ sk_sp<SkImage> DeferredImageDecoder::createFrameAtIndex(size_t index)
     return SkImage::MakeFromBitmap(frame->bitmap());
 }
 
+bool DeferredImageDecoder::clear()
+{
+    if (!m_rwBuffer)
+        return false;
+    m_rwBuffer.reset();
+    m_isBufferCleared = true;
+    return true;
+}
+
 PassRefPtr<SharedBuffer> DeferredImageDecoder::data()
 {
     if (!m_rwBuffer)
@@ -165,6 +175,7 @@ void DeferredImageDecoder::setDataInternal(PassRefPtr<SharedBuffer> passData, bo
             length; length = data->getSomeData(segment, m_rwBuffer->size())) {
             m_rwBuffer->append(segment, length);
         }
+        m_isBufferCleared = false;
     }
 }
 
@@ -324,6 +335,7 @@ sk_sp<SkImage> DeferredImageDecoder::createFrameImageAtIndex(size_t index, bool
     ASSERT(decodedSize.width() > 0);
     ASSERT(decodedSize.height() > 0);
 
+    DCHECK(!m_isBufferCleared);
     sk_sp<SkROBuffer> roBuffer(m_rwBuffer->newRBufferSnapshot());
     RefPtr<SegmentReader> segmentReader = SegmentReader::createFromSkROBuffer(std::move(roBuffer));
     DecodingImageGenerator* generator = new DecodingImageGenerator(m_frameGenerator, imageInfoFrom(decodedSize, knownToBeOpaque), segmentReader.release(), m_allDataReceived, index, m_frameData[index].m_uniqueID);