Implement requestAnimationFrame

Cherry-pick from webkit-org branch on Code Aurora Forum:

requestAnimationFrame doesn't throttle on Mac
https://www.codeaurora.org/gitweb/quic/la/?p=platform/external/webkit.git;a=commit;h=d9dca741b4762c433ae18f7a1bc59a3a81861fc8

Timestamp parameter to requestAnimationFrame is busted in USE(REQUEST_ANIMATION_FRAME_TIMER) path
https://www.codeaurora.org/gitweb/quic/la/?p=platform/external/webkit.git;a=commit;h=f0909a46fa167c84062c63caffef340a6054bc1e

Rename webkitCancelRequestAnimationFrame to webkitCancelAnimationFrame to match spec change
https://www.codeaurora.org/gitweb/quic/la/?p=platform/external/webkit.git;a=commit;h=cd5d11d662d638b3e4dfda33f23cda907f007f12

Remove partially implemented per-Element visibility checks from requestAnimationFrame logic
https://www.codeaurora.org/gitweb/quic/la/?p=platform/external/webkit.git;a=commit;h=9fb90af3cebd0e595990cded0941d230cf77dcc1

(cherry picked from commit 47ff59a279eab9ae5dd1fd17ce7057431750a0b5)

Change-Id: I7e77200006bb0c4cd4b4209082296c425bd207c1

1 files changed, 44 insertions, 34 deletions

diff --git a/Source/WebCore/dom/ScriptedAnimationController.cpp b/Source/WebCore/dom/ScriptedAnimationController.cpp
index 0c70359..4fbf6d9 100644
--- a/Source/WebCore/dom/ScriptedAnimationController.cpp
+++ b/Source/WebCore/dom/ScriptedAnimationController.cpp
@@ -29,16 +29,29 @@
 #if ENABLE(REQUEST_ANIMATION_FRAME)
 
 #include "Document.h"
-#include "Element.h"
 #include "FrameView.h"
 #include "RequestAnimationFrameCallback.h"
 
+#if USE(REQUEST_ANIMATION_FRAME_TIMER)
+#include <algorithm>
+#include <wtf/CurrentTime.h>
+
+using namespace std;
+
+// Allow a little more than 60fps to make sure we can at least hit that frame rate.
+#define MinimumAnimationInterval 0.015
+#endif
+
 namespace WebCore {
 
 ScriptedAnimationController::ScriptedAnimationController(Document* document)
     : m_document(document)
     , m_nextCallbackId(0)
     , m_suspendCount(0)
+#if USE(REQUEST_ANIMATION_FRAME_TIMER)
+    , m_animationTimer(this, &ScriptedAnimationController::animationTimerFired)
+    , m_lastAnimationFrameTime(0)
+#endif
 {
 }
 
@@ -51,20 +64,17 @@ void ScriptedAnimationController::resume()
 {
     --m_suspendCount;
     if (!m_suspendCount && m_callbacks.size())
-        if (FrameView* fv = m_document->view())
-            fv->scheduleAnimation();
+        scheduleAnimation();
 }
 
-ScriptedAnimationController::CallbackId ScriptedAnimationController::registerCallback(PassRefPtr<RequestAnimationFrameCallback> callback, Element* animationElement)
+ScriptedAnimationController::CallbackId ScriptedAnimationController::registerCallback(PassRefPtr<RequestAnimationFrameCallback> callback)
 {
     ScriptedAnimationController::CallbackId id = m_nextCallbackId++;
     callback->m_firedOrCancelled = false;
     callback->m_id = id;
-    callback->m_element = animationElement;
     m_callbacks.append(callback);
     if (!m_suspendCount)
-        if (FrameView* view = m_document->view())
-            view->scheduleAnimation();
+        scheduleAnimation();
     return id;
 }
 
@@ -83,37 +93,19 @@ void ScriptedAnimationController::serviceScriptedAnimations(DOMTimeStamp time)
 {
     if (!m_callbacks.size() || m_suspendCount)
         return;
-    // We want to run the callback for all elements in the document that have registered
-    // for a callback and that are visible.  Running the callbacks can cause new callbacks
-    // to be registered, existing callbacks to be cancelled, and elements to gain or lose
-    // visibility so this code has to iterate carefully.
-
-    // FIXME: Currently, this code doesn't do any visibility tests beyond checking display:
 
     // First, generate a list of callbacks to consider.  Callbacks registered from this point
     // on are considered only for the "next" frame, not this one.
     CallbackList callbacks(m_callbacks);
 
-    // Firing the callback may cause the visibility of other elements to change.  To avoid
-    // missing any callbacks, we keep iterating through the list of candiate callbacks and firing
-    // them until nothing new becomes visible.
-    bool firedCallback;
-    do {
-        firedCallback = false;
-        // A previous iteration may have invalidated style (or layout).  Update styles for each iteration
-        // for now since all we check is the existence of a renderer.
-        m_document->updateStyleIfNeeded();
-        for (size_t i = 0; i < callbacks.size(); ++i) {
-            RequestAnimationFrameCallback* callback = callbacks[i].get();
-            if (!callback->m_firedOrCancelled && (!callback->m_element || callback->m_element->renderer())) {
-                callback->m_firedOrCancelled = true;
-                callback->handleEvent(time);
-                firedCallback = true;
-                callbacks.remove(i);
-                break;
-            }
+    for (size_t i = 0; i < callbacks.size(); ++i) {
+        RequestAnimationFrameCallback* callback = callbacks[i].get();
+        if (!callback->m_firedOrCancelled) {
+            callback->m_firedOrCancelled = true;
+            callback->handleEvent(time);
         }
-    } while (firedCallback);
+    }
+    m_document->updateStyleIfNeeded();
 
     // Remove any callbacks we fired from the list of pending callbacks.
     for (size_t i = 0; i < m_callbacks.size();) {
@@ -124,10 +116,28 @@ void ScriptedAnimationController::serviceScriptedAnimations(DOMTimeStamp time)
     }
 
     if (m_callbacks.size())
-        if (FrameView* view = m_document->view())
-            view->scheduleAnimation();
+        scheduleAnimation();
 }
 
+void ScriptedAnimationController::scheduleAnimation()
+{
+#if USE(REQUEST_ANIMATION_FRAME_TIMER)
+    double scheduleDelay = max<double>(MinimumAnimationInterval - (currentTime() - m_lastAnimationFrameTime), 0);
+    m_animationTimer.startOneShot(scheduleDelay);
+#else
+    if (FrameView* frameView = m_document->view())
+        frameView->scheduleAnimation();
+#endif
+}
+
+#if USE(REQUEST_ANIMATION_FRAME_TIMER)
+void ScriptedAnimationController::animationTimerFired(Timer<ScriptedAnimationController>*)
+{
+    m_lastAnimationFrameTime = currentTime();
+    serviceScriptedAnimations(convertSecondsToDOMTimeStamp(m_lastAnimationFrameTime));
+}
+#endif
+
 }
 
 #endif