Changes subtreeShouldRenderToSeparateSurface logic to account for explicit clipping

cc/texture_draw_quad.cc

Index: cc/texture_draw_quad.cc
diff --git a/cc/texture_draw_quad.cc b/cc/texture_draw_quad.cc
index 5ad73b69dc28731925dcf31518cd61148feedc72..f5788d84dddb5b44dc0c4933f30bb897440cc407 100644
--- a/cc/texture_draw_quad.cc
+++ b/cc/texture_draw_quad.cc
@@ -61,19 +61,17 @@ const TextureDrawQuad* TextureDrawQuad::MaterialCast(
 bool TextureDrawQuad::PerformClipping() {
   // This only occurs if the rect is only scaled and translated (and thus still
   // axis aligned).
-  if (!quadTransform().IsScaleOrTranslation())
+  if (!quadTransform().IsPositiveScaleOrTranslation())
     return false;
 
   // Grab our scale and make sure it's positive.
-  float x_scale = quadTransform().matrix().getDouble(0,0);
-  float y_scale = quadTransform().matrix().getDouble(1,1);
-  if (x_scale <= 0.0f || y_scale <= 0.0f)
-    return false;
+  float x_scale = static_cast<float>(quadTransform().matrix().getDouble(0, 0));
+  float y_scale = static_cast<float>(quadTransform().matrix().getDouble(1, 1));
 
   // Grab our offset.
   gfx::Vector2dF offset(
-      quadTransform().matrix().getDouble(0,3),
-      quadTransform().matrix().getDouble(1,3));
+      static_cast<float>(quadTransform().matrix().getDouble(0, 3)),
+      static_cast<float>(quadTransform().matrix().getDouble(1, 3)));
 
   // Transform the rect by the scale and offset.
   gfx::RectF rectF = rect;