Changes subtreeShouldRenderToSeparateSurface logic to account for explicit clipping

ui/gfx/transform.h

Index: ui/gfx/transform.h
diff --git a/ui/gfx/transform.h b/ui/gfx/transform.h
index 95de30fa3f4c0d3275c19cd61c3e4663f232c38f..a9e5997114f21414291c7ee2afe8394986bc3ece 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -91,6 +91,15 @@ class UI_EXPORT Transform {
     return !(matrix_.getType() & ~SkMatrix44::kTranslate_Mask);
   }
 
+  // Returns true if the matrix is either a positive scale and/or a translation.
+  bool IsPositiveScaleOrTranslation() const {
+    if (!IsScaleOrTranslation())
+      return false;
+    return matrix_.getDouble(0, 0) > 0.0 &&
+        matrix_.getDouble(1, 1) > 0.0 &&
+        matrix_.getDouble(2, 2) > 0.0;
+  }
+
   // Returns true if the matrix is either identity or pure, non-fractional
   // translation.
   bool IsIdentityOrIntegerTranslation() const;