DevTools [Canvas Profile] Fix CanvasProfile control button issue

Canvas profiler control button should be "Take Snapshot" in Single Frame mode.

Contributed by pan.deng@intel.com

BUG=239739

Review URL: https://chromiumcodereview.appspot.com/14619029

git-svn-id: svn://svn.chromium.org/blink/trunk@151221 bbb929c8-8fbe-4397-9dbb-9b2b20218538
3 files changed