Avoid passing uninitialized value to markRectAsNonOpaque.

Source/platform/graphics/skia/OpaqueRegionSkia.cpp

Index: Source/platform/graphics/skia/OpaqueRegionSkia.cpp
diff --git a/Source/platform/graphics/skia/OpaqueRegionSkia.cpp b/Source/platform/graphics/skia/OpaqueRegionSkia.cpp
index 24c0369d2ee641c597367d4f4541d6d0d6364fa1..5ccacbe40bd4745b6b423016c17831467aea09fe 100644
--- a/Source/platform/graphics/skia/OpaqueRegionSkia.cpp
+++ b/Source/platform/graphics/skia/OpaqueRegionSkia.cpp
@@ -156,8 +156,10 @@ static inline bool paintIsOpaque(const SkPaint& paint, OpaqueRegionSkia::DrawTyp
 static inline bool getDeviceClipAsRect(const GraphicsContext* context, SkRect& deviceClipRect)
 {
     // Get the current clip in device coordinate space.
-    if (!context->canvas()->isClipRect())
+    if (!context->canvas()->isClipRect()) {
+        deviceClipRect.setEmpty();
         return false;
+    }
 
     SkIRect deviceClipIRect;
     if (context->canvas()->getClipDeviceBounds(&deviceClipIRect))
@@ -331,7 +333,7 @@ void OpaqueRegionSkia::applyOpaqueRegionFromLayer(const GraphicsContext* context
     SkRect deviceClipRect;
     bool deviceClipIsARect = getDeviceClipAsRect(context, deviceClipRect);
 
-    if (deviceClipRect.isEmpty())
+    if (deviceClipRect.isEmpty() && deviceClipIsARect)

[danakj, 2014/07/28 14:03:57]

reverse this order

[sohanjg, 2014/07/30 10:23:46]

Done.

         return;
 
     SkRect sourceOpaqueRect = layerOpaqueRect;
@@ -339,11 +341,9 @@ void OpaqueRegionSkia::applyOpaqueRegionFromLayer(const GraphicsContext* context
     SkRect destinationOpaqueRect = currentTrackingOpaqueRect();
 
     bool outsideSourceOpaqueRectPreservesOpaque = xfermodePreservesOpaque(paint, false);
-    if (!outsideSourceOpaqueRectPreservesOpaque)
-        markRectAsNonOpaque(deviceClipRect);
+    if (!outsideSourceOpaqueRectPreservesOpaque && !deviceClipIsARect)
+        markAllAsNonOpaque();

[danakj, 2014/07/28 14:03:56]

if it is a rect, you need to still do what we did before. 

if it's not you need to return after marking all.

[sohanjg, 2014/07/30 10:23:46]

Done.

 
-    if (!deviceClipIsARect)
-        return;
     if (!sourceOpaqueRect.intersect(deviceClipRect))
         return;