Avoiding multiple text/string parsing while creating TextRun. When TextRun is created we parse Text String but we are not storing CodePath. In InlineTextBox check was missing for Simple Code Path due to which multiple calls were made to "CodePath" to get code path for current text. Plus when
Run is made with complete string we can store CodePath and use the same.

Bug=330502

Review URL: https://codereview.chromium.org/111833006

git-svn-id: svn://svn.chromium.org/blink/trunk@165203 bbb929c8-8fbe-4397-9dbb-9b2b20218538