Unify clipping return value behavior - true if not empty

bug:22035484

Change-Id: I23ecca38554a60c590181290900deb0e2c48cea1
diff --git a/libs/hwui/SkiaCanvas.cpp b/libs/hwui/SkiaCanvas.cpp
index a323065..6cf66cd 100644
--- a/libs/hwui/SkiaCanvas.cpp
+++ b/libs/hwui/SkiaCanvas.cpp
@@ -419,12 +419,12 @@
 bool SkiaCanvas::clipRect(float left, float top, float right, float bottom, SkRegion::Op op) {
     SkRect rect = SkRect::MakeLTRB(left, top, right, bottom);
     mCanvas->clipRect(rect, op);
-    return mCanvas->isClipEmpty();
+    return !mCanvas->isClipEmpty();
 }
 
 bool SkiaCanvas::clipPath(const SkPath* path, SkRegion::Op op) {
     mCanvas->clipPath(*path, op);
-    return mCanvas->isClipEmpty();
+    return !mCanvas->isClipEmpty();
 }
 
 bool SkiaCanvas::clipRegion(const SkRegion* region, SkRegion::Op op) {
@@ -438,7 +438,7 @@
     } else {
         mCanvas->clipRect(SkRect::MakeEmpty(), op);
     }
-    return mCanvas->isClipEmpty();
+    return !mCanvas->isClipEmpty();
 }
 
 // ----------------------------------------------------------------------------