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 2be72efd0d7bf91c51409f574ac37f52a9820297..6e69c9df400ce89830f96393ef915dee4da15f0c 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -78,6 +78,15 @@ class UI_EXPORT Transform {
     return !(matrix_.getType() & ~SkMatrix44::kTranslate_Mask);
   }
 
+  // Returns trus if the matrix is either a scale and/or translation
+  bool IsPositiveScaleOrTranslation() const {

[danakj, 2012/12/15 18:49:12]

Could you add a unit test in ui/gfx/transform_unittest.cc please?

+    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;