Merge WebKit at r63859 : Initial merge by git.

Change-Id: Ie8096c63ec7c991c9a9cba8bdd9c3b74a3b8ed62

3 files changed, 21 insertions, 3 deletions

diff --git a/WebCore/platform/graphics/skia/ImageBufferSkia.cpp b/WebCore/platform/graphics/skia/ImageBufferSkia.cpp
index 912fd12..f8192fe 100644
--- a/WebCore/platform/graphics/skia/ImageBufferSkia.cpp
+++ b/WebCore/platform/graphics/skia/ImageBufferSkia.cpp
@@ -74,7 +74,10 @@ ImageBuffer::ImageBuffer(const IntSize& size, ImageColorSpace imageColorSpace, b
     // Make the background transparent. It would be nice if this wasn't
     // required, but the canvas is currently filled with the magic transparency
     // color. Can we have another way to manage this?
-    m_data.m_canvas.drawARGB(0, 0, 0, 0, SkXfermode::kClear_Mode);
+    //
+    // Avoid drawing on a zero-sized canvas. Skia can't handle it.
+    if (!size.isZero())
+        m_data.m_canvas.drawARGB(0, 0, 0, 0, SkXfermode::kClear_Mode);
     success = true;
 }
 
diff --git a/WebCore/platform/graphics/skia/PathSkia.cpp b/WebCore/platform/graphics/skia/PathSkia.cpp
index a0d4c79..12241f8 100644
--- a/WebCore/platform/graphics/skia/PathSkia.cpp
+++ b/WebCore/platform/graphics/skia/PathSkia.cpp
@@ -74,6 +74,13 @@ bool Path::hasCurrentPoint() const
     return m_path->getPoints(NULL, 0) != 0;
 }
 
+FloatPoint Path::currentPoint() const 
+{
+    // FIXME: return current point of subpath.
+    float quietNaN = std::numeric_limits<float>::quiet_NaN();
+    return FloatPoint(quietNaN, quietNaN);
+}
+
 bool Path::contains(const FloatPoint& point, WindRule rule) const
 {
     return SkPathContainsPoint(m_path, point,
diff --git a/WebCore/platform/graphics/skia/SkiaUtils.cpp b/WebCore/platform/graphics/skia/SkiaUtils.cpp
index 0c6b2d6..b16a344 100644
--- a/WebCore/platform/graphics/skia/SkiaUtils.cpp
+++ b/WebCore/platform/graphics/skia/SkiaUtils.cpp
@@ -129,10 +129,18 @@ static U8CPU InvScaleByte(U8CPU component, uint32_t scale)
 
 SkColor SkPMColorToColor(SkPMColor pm)
 {
-    if (0 == pm)
+    if (!pm)
         return 0;
-    
     unsigned a = SkGetPackedA32(pm);
+    if (!a) {
+        // A zero alpha value when there are non-zero R, G, or B channels is an
+        // invalid premultiplied color (since all channels should have been
+        // multiplied by 0 if a=0).
+        SkASSERT(false); 
+        // In production, return 0 to protect against division by zero.
+        return 0;
+    }
+    
     uint32_t scale = (255 << 16) / a;
     
     return SkColorSetARGB(a,