Web Animations API: Start implementation of Element.animate().

Source/core/animation/ElementAnimation.cpp

+/*
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+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "core/animation/ElementAnimation.h"
+
+#include "core/animation/DocumentTimeline.h"
+#include "core/css/CSSParser.h"
+#include "core/css/resolver/StyleResolver.h"
+#include "wtf/text/StringBuilder.h"
+
+
+namespace WebCore {
+
+void ElementAnimation::animate(Element* element, Vector<Dictionary> keyframeDictionaryVector)
+{
+    ASSERT(RuntimeEnabledFeatures::webAnimationsAPIEnabled());
+
+    KeyframeAnimationEffect::KeyframeVector keyframes;
+    Vector<RefPtr<MutableStylePropertySet> > propertySetVector;
+
+    for (size_t i = 0; i < keyframeDictionaryVector.size(); ++i) {
+        RefPtr<MutableStylePropertySet> propertySet = MutableStylePropertySet::create();
+        propertySetVector.append(propertySet);
+
+        RefPtr<Keyframe> keyframe = Keyframe::create();
+        keyframes.append(keyframe);
+
+        double offset;
+        if (keyframeDictionaryVector[i].get("offset", offset))
+            keyframe->setOffset(offset);
+        else
+            RELEASE_ASSERT_WITH_MESSAGE(false, "Web Animations not yet implemented: Handling for keyframes without specified offset.");

[esprehn, 2013/12/09 18:51:25]

Can you hit this with JS today if you turn the flag on? You should never be able
to crash a shipping build on an ASSERT even for features that are not done yet.

[shans, 2013/12/09 23:25:57]

This feature is behind the experimental web platform features flag. What do you
propose is the appropriate mechanism for bailing cleanly when partially
implemented (and off-by-default) features wish to expose JavaScript APIs?

[Steve Block, 2013/12/09 23:32:20]

Yes, you can.

Is this policy documented somewhere? When implementing the Web Animations model
we used this approach to make sure that not-yet-implemented features didn't get
forgotten about, and it worked rather well. I guess the alternative is a debug
assertion and early-out.

[esprehn, 2013/12/09 23:36:16]

We should never ship something that we know will crash the renderer and is
available from script. This could mean that a popular page with a demo starts
crashing thousands of people on Canary and floods go/crash.

[shans, 2013/12/09 23:41:27]

It can only crash for people who have the flag enabled.

Again, though, what is your proposed alternative? The specific case here is that
we wish to pursue an incremental implementation approach - in the short term
there is going to be stuff that just isn't implemented. How do we gracefully
deal with JavaScript requests that tickle unimplemented features?

[rjwright, 2013/12/10 03:05:40]

Done.

+
+        String compositeString;
+        keyframeDictionaryVector[i].get("composite", compositeString);
+        if (compositeString == String("add"))
+            keyframe->setComposite(AnimationEffect::CompositeAdd);
+
+        Vector<String> keyframeProperties;
+        keyframeDictionaryVector[i].getOwnPropertyNames(keyframeProperties);
+
+        for (size_t j = 0; j < keyframeProperties.size(); ++j) {
+            String property = keyframeProperties[j];
+            CSSPropertyID id = camelCaseCSSPropertyNameToID(property.impl());
+
+            // FIXME: There is no way to store invalid properties or invalid values
+            // in a Keyframe object, so for now I just skip over them. Eventually we
+            // will need to support getFrames(), which should return exactly the
+            // keyframes that were input through the API. We will add a layer to wrap
+            // KeyframeAnimationEffect, store input keyframes and implement getFrames.
+            if (id == CSSPropertyInvalid || !CSSAnimations::isAnimatableProperty(id))
+                continue;
+
+            String value;
+            keyframeDictionaryVector[i].get(property, value);
+            if (!CSSParser::parseValue(propertySet.get(), id, value, false, element->document()))
+                continue;

[esprehn, 2013/12/09 18:51:25]

This continue doesn't matter, you're at the end of the loop. Also you shouldn't
need to call the parser directly, MutableStylePropertySet::setProperty handles
parsing internally, just use setProperty(id, value)

[rjwright, 2013/12/10 03:05:40]

Done.

+        }
+    }
+
+    StyleResolver::setKeyframePropertyValues(element, propertySetVector, keyframes);
+    RefPtr<KeyframeAnimationEffect> effect = KeyframeAnimationEffect::create(keyframes);

[esprehn, 2013/12/09 18:51:25]

This should be the return value of the styleResolver method.

RefPtr<KeyframeAnimationEffect> ... = StyleResolver::createKeyframes(...);

[rjwright, 2013/12/10 03:05:40]

Done.

+
+    // FIXME: Totally hardcoded Timing for now. Will handle timing parameters later.
+    Timing timing;
+    timing.hasIterationDuration = true;
+    timing.iterationDuration = 1;
+
+    RefPtr<Animation> animation = Animation::create(element, effect, timing);
+    DocumentTimeline* timeline = element->document().timeline();
+    ASSERT(timeline);
+    timeline->play(animation.get());
+}
+
+} // namespace WebCore