1 files changed, 16 insertions, 33 deletions

diff --git a/WebKit/android/nav/CacheBuilder.cpp b/WebKit/android/nav/CacheBuilder.cpp
index cbc580d..52ee72c 100644
--- a/WebKit/android/nav/CacheBuilder.cpp
+++ b/WebKit/android/nav/CacheBuilder.cpp
@@ -55,6 +55,7 @@
 #include "RenderListBox.h"
 #include "RenderSkinCombo.h"
 #include "RenderTextControl.h"
+#include "RenderView.h"
 #include "RenderWidget.h"
 #include "SkCanvas.h"
 #include "SkPoint.h"
@@ -94,7 +95,9 @@ Frame* CacheBuilder::FrameAnd(const CacheBuilder* cacheBuilder) {
 }
 
 CacheBuilder::LayerTracker::~LayerTracker() {
-    if (mRenderLayer)
+    // Check for a stacking context to prevent a crash in layers without a
+    // parent.
+    if (mRenderLayer && mRenderLayer->stackingContext())
         // Restore the scroll position of the layer.  Does not affect layers
         // without overflow scroll as the layer will not be scrolled.
         mRenderLayer->scrollToOffset(mScroll.x(), mScroll.y(), false, false);
@@ -1023,6 +1026,13 @@ void CacheBuilder::BuildFrame(Frame* root, Frame* frame,
         cachedRoot->setFocusBounds(focused->getRect());
     int globalOffsetX, globalOffsetY;
     GetGlobalOffset(frame, &globalOffsetX, &globalOffsetY);
+#if USE(ACCELERATED_COMPOSITING)
+    // The frame itself might be composited so we need to track the layer.  Do
+    // not track the base frame's layer as the main content is draw as part of
+    // BaseLayerAndroid's picture.
+    if (frame != root && frame->contentRenderer()->usesCompositing() && node->lastChild())
+        TrackLayer(layerTracker, frame->contentRenderer(), node->lastChild(), globalOffsetX, globalOffsetY);
+#endif
     while (walk.mMore || (node = node->traverseNextNode()) != NULL) {
 #if DUMP_NAV_CACHE
         nodeIndex++;
@@ -1105,37 +1115,8 @@ void CacheBuilder::BuildFrame(Frame* root, Frame* frame,
 #if USE(ACCELERATED_COMPOSITING)
             // If this renderer has its own layer and the layer is composited,
             // start tracking it.
-            if (lastChild && nodeRenderer->hasLayer() && toRenderBox(nodeRenderer)->layer()->backing()) {
-                TrackLayer(layerTracker, nodeRenderer, lastChild,
-                    globalOffsetX, globalOffsetY);
-                size_t size = tracker.size();
-                LayerAndroid* layer = layerTracker.last().mLayer;
-                if (layer) {
-                    int id = layer->uniqueId();
-                    const RenderLayer* renderLayer =
-                            layerTracker.last().mRenderLayer;
-                    // Global location
-                    IntPoint loc = renderLayer->absoluteBoundingBox().location();
-                    loc.move(globalOffsetX, globalOffsetY);
-                    // if this is a child of a CachedNode, add a layer
-                    size_t limit = cachedFrame->layerCount() == 0 ? 0 :
-                        cachedFrame->lastLayer()->cachedNodeIndex();
-                    for (size_t index = 1; index < tracker.size(); index++) {
-                        const FocusTracker& cursorNode = tracker.at(index);
-                        size_t index = cursorNode.mCachedNodeIndex;
-                        if (index <= limit) { // already added?
-                            DBG_NAV_LOGD("index=%d limit=%d id=%d", index,
-                                limit, id);
-                            continue;
-                        }
-                        DBG_NAV_LOGD("call add layer %d", id);
-                        CachedNode* trackedNode = cachedFrame->getIndex(index);
-                        trackedNode->setIsInLayer(true);
-                        trackedNode->setIsUnclipped(true);
-                        AddLayer(cachedFrame, index, loc, id);
-                    }
-                }
-            }
+            if (lastChild && nodeRenderer->hasLayer() && toRenderBox(nodeRenderer)->layer()->backing())
+                TrackLayer(layerTracker, nodeRenderer, lastChild, globalOffsetX, globalOffsetY);
 #endif
         }
         bool more = walk.mMore;
@@ -2936,7 +2917,9 @@ void CacheBuilder::TrackLayer(WTF::Vector<LayerTracker>& layerTracker,
         aLayer = aLayer->getChild(0)->getChild(0);
     if (!aLayer)
         return;
-    layer->scrollToOffset(0, 0, false, false);
+    // Prevent a crash when scrolling a layer that does not have a parent.
+    if (layer->stackingContext())
+        layer->scrollToOffset(0, 0, false, false);
 #endif
     layerTracker.grow(layerTracker.size() + 1);
     LayerTracker& indexTracker = layerTracker.last();