High CPU and increased memory usage fix for high-res (GIF, WEBP...) animations.

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

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 39 matching lines @@
     RefPtr<BitmapImage> result = adoptRef(new BitmapImage(bitmap));
     result->m_frames[0].m_orientation = orientation;
     if (orientation.usesWidthAsHeight())
         result->m_sizeRespectingOrientation = result->m_size.transposedSize();
     return result.release();
 }
 
 BitmapImage::BitmapImage(ImageObserver* observer)
     : Image(observer)
     , m_currentFrame(0)
+    , m_cachedFrameIndex(0)
     , m_repetitionCount(cAnimationNone)
     , m_repetitionCountStatus(Unknown)
     , m_repetitionsComplete(0)
     , m_desiredFrameStartTime(0)
     , m_frameCount(0)
     , m_animationPolicy(ImageAnimationPolicyAllowed)
     , m_animationFinished(false)
     , m_allDataReceived(false)
     , m_haveSize(false)
     , m_sizeAvailable(false)
     , m_hasUniformFrameSize(true)
     , m_haveFrameCount(false)
 {
 }
 
 BitmapImage::BitmapImage(const SkBitmap& bitmap, ImageObserver* observer)
     : Image(observer)
     , m_size(bitmap.width(), bitmap.height())
     , m_currentFrame(0)
+    , m_cachedFrame(adoptRef(SkImage::NewFromBitmap(bitmap)))
+    , m_cachedFrameIndex(0)
     , m_repetitionCount(cAnimationNone)
     , m_repetitionCountStatus(Unknown)
     , m_repetitionsComplete(0)
     , m_frameCount(1)
     , m_animationPolicy(ImageAnimationPolicyAllowed)
     , m_animationFinished(true)
     , m_allDataReceived(true)
     , m_haveSize(true)
     , m_sizeAvailable(true)
     , m_haveFrameCount(true)
 {
     // Since we don't have a decoder, we can't figure out the image orientation.
     // Set m_sizeRespectingOrientation to be the same as m_size so it's not 0x0.
     m_sizeRespectingOrientation = m_size;
 
     m_frames.grow(1);
     m_frames[0].m_hasAlpha = !bitmap.isOpaque();
-    m_frames[0].m_frame = adoptRef(SkImage::NewFromBitmap(bitmap));
     m_frames[0].m_haveMetadata = true;
 }
 
 BitmapImage::~BitmapImage()
 {
     stopAnimation();
 }
 
 bool BitmapImage::currentFrameHasSingleSecurityOrigin() const
 {
     return true;
 }
 
-void BitmapImage::destroyDecodedData(bool destroyAll)
+void BitmapImage::destroyDecodedData()
 {
-    for (size_t i = 0; i < m_frames.size(); ++i) {
-        // The underlying frame isn't actually changing (we're just trying to
-        // save the memory for the framebuffer data), so we don't need to clear
-        // the metadata.
-        m_frames[i].clear(false);
-    }
-
-    m_source.clearCacheExceptFrame(destroyAll ? kNotFound : m_currentFrame);
+    m_cachedFrame.clear();
+    for (size_t i = 0; i < m_frames.size(); ++i)
+        m_frames[i].clear(true);
+    m_source.clearCacheExceptFrame(kNotFound);
     notifyMemoryChanged();
 }
 
-void BitmapImage::destroyDecodedDataIfNecessary()
-{
-    // Animated images >5MB are considered large enough that we'll only hang on
-    // to one frame at a time.
-    static const size_t cLargeAnimationCutoff = 5242880;
-    size_t allFrameBytes = 0;
-    for (size_t i = 0; i < m_frames.size(); ++i)
-        allFrameBytes += m_frames[i].m_frameBytes;
-
-    if (allFrameBytes > cLargeAnimationCutoff) {
-        destroyDecodedData(false);
-    }
-}
-
 void BitmapImage::notifyMemoryChanged()
 {
     if (getImageObserver())
         getImageObserver()->decodedSizeChangedTo(this, totalFrameBytes());
 }
 
 size_t BitmapImage::totalFrameBytes()
 {
     const size_t numFrames = frameCount();
     size_t totalBytes = 0;
     for (size_t i = 0; i < numFrames; ++i)
         totalBytes += m_source.frameBytesAtIndex(i);
     return totalBytes;
 }
 
-void BitmapImage::cacheFrame(size_t index)
+PassRefPtr<SkImage> BitmapImage::decodeAndCacheFrame(size_t index)
 {
     size_t numFrames = frameCount();
     if (m_frames.size() < numFrames)
         m_frames.grow(numFrames);
 
     // We are caching frame snapshots.  This is OK even for partially decoded frames,
     // as they are cleared by dataChanged() when new data arrives.
-    m_frames[index].m_frame = m_source.createFrameAtIndex(index);
+    RefPtr<SkImage> image = m_source.createFrameAtIndex(index);
+    m_cachedFrame = image;
+    m_cachedFrameIndex = index;
 
     m_frames[index].m_orientation = m_source.orientationAtIndex(index);
     m_frames[index].m_haveMetadata = true;
     m_frames[index].m_isComplete = m_source.frameIsCompleteAtIndex(index);
     if (repetitionCount(false) != cAnimationNone)
         m_frames[index].m_duration = m_source.frameDurationAtIndex(index);
     m_frames[index].m_hasAlpha = m_source.frameHasAlphaAtIndex(index);
     m_frames[index].m_frameBytes = m_source.frameBytesAtIndex(index);
 
     const IntSize frameSize(index ? m_source.frameSizeAtIndex(index) : m_size);
     if (frameSize != m_size)
         m_hasUniformFrameSize = false;
 
     notifyMemoryChanged();
+    return image.release();
 }
 
 void BitmapImage::updateSize() const
 {
     if (!m_sizeAvailable || m_haveSize)
         return;
 
     m_size = m_source.size();
     m_sizeRespectingOrientation = m_source.size(RespectImageOrientation);
     m_haveSize = true;
@@ skipping 34 matching lines @@
     // and the frames aren't even guaranteed to appear in the file in the same
     // order as in the directory, so an arbitrary number of the frames might be
     // incomplete (if we ask for frames for which we've not yet reached the
     // start of the frame data), and any or none of them might be the particular
     // frame affected by appending new data here. Thus we have to clear all the
     // incomplete frames to be safe.
     for (size_t i = 0; i < m_frames.size(); ++i) {
         // NOTE: Don't call frameIsCompleteAtIndex() here, that will try to
         // decode any uncached (i.e. never-decoded or
         // cleared-on-a-previous-pass) frames!
-        if (m_frames[i].m_haveMetadata && !m_frames[i].m_isComplete)
+        if (m_frames[i].m_haveMetadata && !m_frames[i].m_isComplete) {
             m_frames[i].clear(true);
+            if (i == m_cachedFrameIndex)
+                m_cachedFrame.clear();

[scroggo_chromium, 2016/05/04 21:15:54]

Should we set m_cachedFrameIndex to an invalid value?

[aleksandar.stojiljkovic, 2016/05/04 21:28:07]

No need, once a non null value is assigned to it a valid index will be assigned
to m_cachedFrameIndex.

+        }
     }
 
     // Feed all the data we've seen so far to the image decoder.
     m_allDataReceived = allDataReceived;
     ASSERT(data());
     m_source.setData(*data(), allDataReceived);
 
     m_haveFrameCount = false;
     m_hasUniformFrameSize = true;
     return isSizeAvailable();
@@ skipping 43 matching lines @@
             // the image, as it was needed for page layout, so we need to reverse it back here.
             adjustedDstRect = FloatRect(adjustedDstRect.x(), adjustedDstRect.y(), adjustedDstRect.height(), adjustedDstRect.width());
         }
     }
 
     SkRect skSrcRect = adjustedSrcRect;
     canvas->drawImageRect(image.get(), skSrcRect, adjustedDstRect, &paint,
         WebCoreClampingModeToSkiaRectConstraint(clampMode));
     canvas->restoreToCount(initialSaveCount);
 
-    if (currentFrameIsLazyDecoded())
+    if (image->isLazyGenerated())
         PlatformInstrumentation::didDrawLazyPixelRef(image->uniqueID());
 
     if (ImageObserver* observer = getImageObserver())
         observer->didDraw(this);
 
     startAnimation();
 }
 
 size_t BitmapImage::frameCount()
 {
@@ skipping 21 matching lines @@
 
     if (m_sizeAvailable && hasVisibleImageSize(size())) {
         BitmapImageMetrics::countDecodedImageType(m_source.filenameExtension());
         if (m_source.filenameExtension() == "jpg")
             BitmapImageMetrics::countImageOrientation(m_source.orientationAtIndex(0).orientation());
     }
 
     return m_sizeAvailable;
 }
 
-bool BitmapImage::ensureFrameIsCached(size_t index)
-{
-    if (index >= frameCount())
-        return false;
-
-    if (index >= m_frames.size() || !m_frames[index].m_frame)
-        cacheFrame(index);
-
-    return true;
-}
-
 PassRefPtr<SkImage> BitmapImage::frameAtIndex(size_t index)
 {
-    if (!ensureFrameIsCached(index))
+    if (index >= frameCount())
         return nullptr;
 
-    return m_frames[index].m_frame;
+    if (index == m_cachedFrameIndex && m_cachedFrame)
+        return m_cachedFrame;

[Peter Kasting, 2016/05/07 01:58:29]

Does this implicitly ref m_cachedFrame and then pass back the new ref?  (I want
to make sure we don't pass back the only ref, and I'm not very familiar with the
Blink smart pointer types.)

[aleksandar.stojiljkovic, 2016/05/07 19:50:53]

Yes, see PasRefPtr.h.
 template <typename U> PassRefPtr(const RefPtr<U>&,
EnsurePtrConvertibleArgDecl(U, T));
It is cheaper than to create RefPtr and call .release but basically the same.
Anyway, this all should go away soon.

+
+    return decodeAndCacheFrame(index);
 }
 
 bool BitmapImage::frameIsCompleteAtIndex(size_t index)
 {
     if (index < m_frames.size() && m_frames[index].m_haveMetadata && m_frames[index].m_isComplete)
         return true;
 
     return m_source.frameIsCompleteAtIndex(index);
 }
 
@@ skipping 195 matching lines @@
     m_frameTimer.clear();
 }
 
 void BitmapImage::resetAnimation()
 {
     stopAnimation();
     m_currentFrame = 0;
     m_repetitionsComplete = 0;
     m_desiredFrameStartTime = 0;
     m_animationFinished = false;
-
-    // For extremely large animations, when the animation is reset, we just throw everything away.
-    destroyDecodedDataIfNecessary();
+    m_cachedFrame.clear();
 }
 
 bool BitmapImage::maybeAnimated()
 {
     if (m_animationFinished)
         return false;
     if (frameCount() > 1)
         return true;
 
     return m_source.repetitionCount() != cAnimationNone;
@@ skipping 37 matching lines @@
         // because it is 0 (see comments on its declaration in ImageAnimation.h).
         if ((repetitionCount(true) != cAnimationLoopInfinite && m_repetitionsComplete > m_repetitionCount)
             || (m_animationPolicy == ImageAnimationPolicyAnimateOnce && m_repetitionsComplete > 0)) {
             m_animationFinished = true;
             m_desiredFrameStartTime = 0;
             --m_currentFrame;
             advancedAnimation = false;
         } else
             m_currentFrame = 0;
     }
-    destroyDecodedDataIfNecessary();
 
     // We need to draw this frame if we advanced to it while not skipping, or if
     // while trying to skip frames we hit the last frame and thus had to stop.
     if (skippingFrames != advancedAnimation)
         getImageObserver()->animationAdvanced(this);
+
     return advancedAnimation;
 }
 
 } // namespace blink