FlameChart: Speed up flamechart draw procedure. Reduce the number of fillStyle calls.

On the huge profiles flame chart has to draw number of bars.
Each bar requires 2  calls to the context.fillStyle.
One for color of the current bar and the other for color of the text.
I reduced the number of calls to the context.fillStyle  with help of
splitting the procedure on two parts. One for drawing bars
and the other for drawing texts.

BUG=none
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/23570007

git-svn-id: svn://svn.chromium.org/blink/trunk@157203 bbb929c8-8fbe-4397-9dbb-9b2b20218538
FlameChart: do not jump to the sources if the user has dragged the canvas.

BUG=none
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/23927003

git-svn-id: svn://svn.chromium.org/blink/trunk@157204 bbb929c8-8fbe-4397-9dbb-9b2b20218538
# Enter a description of the change.

FlameChart: style fix.

BUG=none
TBR=yurys@chromium.org

Review URL: https://codereview.chromium.org/23944002

git-svn-id: svn://svn.chromium.org/blink/trunk@157205 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Introduce toSVGViewElement(), and refactor setupInitialView() using it

As a step to clean-up static_cast<SVGXXX>, toSVGTextElement() is added to clean-up
static_cast<SVGTextElement*>. Besides this cl does refactoring duplicated condition checking
in setupInitialView().

BUG=N/A

Review URL: https://chromiumcodereview.appspot.com/23636006

git-svn-id: svn://svn.chromium.org/blink/trunk@157206 bbb929c8-8fbe-4397-9dbb-9b2b20218538