Make webrtc-internals graphs handle float numbers better.
It used to be limited to integer when the value <1024,
now changed to allow up to 2 decimal digits.

BUG=

Review URL: https://codereview.chromium.org/137703013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249528 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249528