Replace SVG bitmap cache with directly-rendered SVG
https://bugs.webkit.org/show_bug.cgi?id=106159

Reviewed by Tim Horton.

Source/WebCore:

This patch removes the caching of SVG bitmaps so SVG images are rendered directly. This
enables WebKit to pass the IE Chalkboard demo in 10s on a Z620:
http://ie.microsoft.com/testdrive/Performance/Chalkboard/

On a simple scaled SVG benchmark similar to the IE10 Chalkboard demo
(http://philbit.com/SvgImagePerformance/viewport.html):
    without patch: ~20FPS
    with patch: ~55FPS

The bitmap SVG image cache had several shortcomings:
    - The bitmap cache prevented viewport rendering. (WK104693)
    - Bitmap memory usage was high. (WK106484)
    - Caching animating images was expensive.

This change removes almost all of the SVGImageCache implementation, replacing it with
directly-rendered SVG. Instead of caching bitmaps, an SVGImageForContainer is cached which
is a thin wrapper around an SVG image with the associated container size and scale.
When rendering patterns (e.g., tiled backgrounds), a temporary bitmap is used for
performance. This change also removes the redraw timer of the old cache, instead relying
on the SVG image to notify clients if the image changes (e.g., during animations).

This patch fixes two existing bugs (WK99481 and WK104189) that were due to caching bitmaps
at a fixed size. A test has been added for each of these bugs.

Tests: svg/as-image/svg-image-scaled.html
       svg/as-image/svg-image-viewbox.html

* CMakeLists.txt:
* GNUmakefile.list.am:
* Target.pri:
* WebCore.gypi:
* WebCore.vcproj/WebCore.vcproj:
* WebCore.xcodeproj/project.pbxproj:
* loader/cache/CachedImage.cpp:
(WebCore::CachedImage::lookupOrCreateImageForRenderer):
(WebCore::CachedImage::setContainerSizeForRenderer):
(WebCore::CachedImage::clear):
(WebCore::CachedImage::changedInRect):

    SVG images are no longer special-cased here. When the SVG image changes, users are
    notified through this function, and users can then request their content to be redrawn.

* svg/graphics/SVGImage.cpp:
(WebCore::SVGImage::setContainerSize):
(WebCore::SVGImage::drawForContainer):

    drawForContainer lays out the SVG content for a specific container size and renders it.
    The logic is fairly straightforward but a note about the scales and zooms here:
        the destination rect parameter is zoomed but not scaled
        the source rect parameter is zoomed but not scaled
        the context is scaled but not zoomed
    SVGImage::draw(...) only accepts a source and destination rect but does not consider
    scale or zoom. Therefore, drawForContainer removes the zoom component from the source
    so SVGImage::draw(...) will draw from the pre-zoom source to the post-zoom destination.

(WebCore::SVGImage::drawPatternForContainer):

    For performance, drawPatternForContainer renders the SVG content onto a bitmap, then
    has the bitmap image draw the pattern. This is necessary because drawPattern is used
    for tiling.

(WebCore):
(WebCore::SVGImage::startAnimation):
(WebCore::SVGImage::stopAnimation):
(WebCore::SVGImage::resetAnimation):
(WebCore::SVGImage::reportMemoryUsage):
* svg/graphics/SVGImage.h:
(WebCore):
(SVGImage):
* svg/graphics/SVGImageCache.cpp:

    Instead of storing a SizeAndScales values for each renderer, a SVGImageForContainer
    is stored which is just a thin wrapper around an SVG image that contains container
    sizing information. By combining the image and size information, the two maps of
    SVGImageCache have been merged into one.

    To make this patch easier to review, SVGImageCache still exists and works similar to
    how it did before the patch. Now, SVGImageCache simply stores the SVGImageForContainers.
    In a followup patch it will be removed.

    Note: the redraw timer of SVGImageCache has been removed because animation
    invalidation is now properly propagated back to the image clients.

(WebCore):
(WebCore::SVGImageCache::SVGImageCache):
(WebCore::SVGImageCache::~SVGImageCache):
(WebCore::SVGImageCache::removeClientFromCache):
(WebCore::SVGImageCache::setContainerSizeForRenderer):
(WebCore::SVGImageCache::imageSizeForRenderer):

    Previously, this function returned the scaled image size which was incorrect. The image
    size is used by clients such as GraphicsContext2D to determine the source size
    for drawing the image. draw() accepts zoomed but not scaled values, so this has been
    changed.

(WebCore::SVGImageCache::imageForRenderer):

    A FIXME has been added here to not set the scale on every lookup. This can be improved
    by setting the page scale factor in setContainerSizeForRenderer() in a future patch.

* svg/graphics/SVGImageCache.h:
(WebCore):
(SVGImageCache):
* svg/graphics/SVGImageForContainer.cpp: Added.
(WebCore):

    SVGImageForContainer is a thin wrapper around an SVG image. The lifetime of the
    SVGImage will be longer than the image cache.

(WebCore::SVGImageForContainer::size):

    This is the only logic in SVGImageForContainer. The size returned needs to be zoomed
    but not scaled because it is used (e.g., by RenderImage) to pass back into draw() which
    takes zoomed but not scaled values.

(WebCore::SVGImageForContainer::draw):
(WebCore::SVGImageForContainer::drawPattern):
* svg/graphics/SVGImageForContainer.h: Added.
(WebCore):
(SVGImageForContainer):

    In a future patch SVGImageForContainer can be made immutable but without a refactoring
    for not setting the page scale factor in SVGImageCache::lookupOrCreateImageForRenderer,
    setters are needed.

(WebCore::SVGImageForContainer::create):
(WebCore::SVGImageForContainer::containerSize):
(WebCore::SVGImageForContainer::pageScale):
(WebCore::SVGImageForContainer::zoom):
(WebCore::SVGImageForContainer::setSize):
(WebCore::SVGImageForContainer::setZoom):
(WebCore::SVGImageForContainer::setPageScale):
(WebCore::SVGImageForContainer::SVGImageForContainer):
(WebCore::SVGImageForContainer::destroyDecodedData):
(WebCore::SVGImageForContainer::decodedSize):

LayoutTests:

This patch fixes two existing bugs (WK99481 and WK104189) that were due to caching bitmaps
at a fixed size. A test has been added for each of these bugs.

* platform/chromium/TestExpectations:
* svg/as-image/svg-image-scaled-expected.html: Added.
* svg/as-image/svg-image-scaled.html: Added.
* svg/as-image/svg-image-viewbox-expected.html: Added.
* svg/as-image/svg-image-viewbox.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142765 268f45cc-cd09-0410-ab3c-d52691b4dbfc