Fix infinite matrix during an invert.

This patch ensures that when inverting a SkMatrix44, we handle small
floats properly. When inverted these can cause infinite values, but
still evaluate to true in an if condition.

BUG=chromium:498516

Review URL: https://codereview.chromium.org/1209763002

1 files changed, 2 insertions, 1 deletions

diff --git a/include/utils/SkMatrix44.h b/include/utils/SkMatrix44.h
index 90f29a994a..2a698f52a2 100644
--- a/include/utils/SkMatrix44.h
+++ b/include/utils/SkMatrix44.h
@@ -358,7 +358,8 @@ public:
     }
 
     /** If this is invertible, return that in inverse and return true. If it is
-        not invertible, return false and ignore the inverse parameter.
+        not invertible, return false and leave the inverse parameter in an
+        unspecified state.
      */
     bool invert(SkMatrix44* inverse) const;